Evidence?
Are you comparing instances of equal complexity?
I.E. It’s not a fair comparison if your reference plugin is playing an unencrypted single layer patch that was sampled at the same clock rate as your project streaming over a single bus with no extra processing; while your halion reference is playing an encrypted, 16 layer, 7 channel surround sound patch, with 4 or 5 effects running in Halion (Like heavy convolution reverbs, multiple compression and distortion effects, amp simulators, etc…with some samples that may have been mastered at a different clock rate from your DAW project, etc…).
Don’t forget that several of the ‘H4’ Factory patches are 7 channel surround sound! Tweak the patches for stereo and save new copies if you don’t need surround sound!
My personal experience is quite different. Halion 5 is the most efficient plugin I have with anywhere near the power and feature set offered. The only thing I’ve run that uses less system resources (with a comparable number of tones being generated or samples played) is ARIA/Sforzando. There’s a pretty big difference in the complexity of the patches and samples I’m running in the two players though. I pile on the effects and layers with Halion…where in ARIA I’m running really lean libraries that were designed and optimized at a time when a dual core ‘Core Duo’ architecture and SATA2 platter drives were considered ‘high end stuff’ for consumers.
I’ve got an ancient AMD Hex core rig running only 8gig of DDR2 memory (all at stock speeds of well under 4ghz), and it doesn’t even break a sweat with very robust instances of Halion 5 (40 or more tracks). I usually track at 24bit 48khz (no need to go higher unless I’m hooking really nice microphones to the rig). My sample libraries are all over the map…some are 44.1khz, some 48khz, etc.
I use Halion 5 in at least 4 different hosts (Cubase, Sibelius, Finale, Bidule) on a regular basis.
In contrast, I have ‘single instrument’ monophonic sample based plugins by several other companies that require massive ASIO buffers of 1meg or larger (in all four of the previously mentioned hosts) to even get a single instance of them working on a single track (needless to say, I can only step input with these plugins…too much latency to play in them live).
I.E. ONE instance of a popular ‘violin section plugin’ (I’ll call it brand X since I’m not into bashing products that I ‘tested’ before I purchased and knew their shortcomings before I got them) is so resource hungry I have to instant render the tracks to use the plugin. If I activate the Brand X plugin’s reverb (which isn’t even convolution based) it’s totally unusable as a live plugin (must instant render). This plugin isn’t surround sound, and it doesn’t include any tools to simulate surround sound (while Halion does). In the brand X plugin(s), the ‘decryption protocols used to play back the protected content’ for a single track alone in at least 3 competing products on my system take more CPU than Halion is using to play back a ‘more lush and robust’ 16 to 20 track Halion Symphonic Orchestra Library based project.
Quite a few of the competing products I have don’t really have a ‘manual’ at all, let alone in dozens of languages! They cost as much as Halion 5 just to get a few orchestra instruments, and I can’t edit them much at all! They have predefined special characteristics that cannot be altered. They have individual samples that are out of tune, cannot tuned or replaced, etc. They have fixed reverb tails that I can’t get rid of or fine control. Any requests for information on how to adjust the disk buffers and such for my older system have either been ignored, or confirmed as ‘not possible’. So called ‘support’ wasn’t any better or worse than Steinberg’s. In short…they said, "You need in the least a mid level Sandy Bridge based rig to run our product (even though their spec sheets simply say ‘a dual core processer’ 3ghz or faster!) Just the CPU on such a rig cost more than my entire PC setup (not counting the software).
So…with the ‘cpu hog’ called Halion, I’m doing quite well on a 12 year old, bottom of the barrel, low end PC. I can’t say the same for many of the other products on the market right now. Alternatives as powerful, efficient, and flexible as Halion are twice the price…and that’s mostly for the privilege of staring at lists of not so great ‘third party libraries’ (again often more expensive than H5) that I’m not very interested in buying (and that come with free players anyway).
My experience is QUITE DIFFERENT.
Note, it did help to
- Read the MANUAL.
- Tweak the CPU, Disk, and Memory settings in Halion to optimal settings for my system (For my rig once an H5 instance needs more than about 400 voices…‘the host’ runs a bit more efficient if I let H5 do its own internal core management).
- Make sure I increase the max polyphony as my project gets larger. 99% of the time, if Halion starts sounding weird or dropping notes…if I look in the Option tab I’ll notice that the project is asking for more voices than the Max setting. Bumping that up to a large enough number fixes it.
As for the ‘if and when they work’ remark…
I do know ONE way to crash H5. Until it gets fixed it’s easy to work around. I hope they release a patch for H5 on all known issues that can ‘crash’ H5. One shouldn’t be required to buy H6 to get these basic fixes!
Putting things in perspective: I also know ways to crash most of the competing plugins that are of equal (and in many cases far simpler) complexity to Halion! Ironically, some of those plugins HAVE released several ‘fixes and updates’ in the past year, but I can still crash them just the same (sometimes the so called ‘updates’ cause more problems than they solve).
Those companies that have gone over to rapid prototyping ‘subscription’ models have been the worst in terms of charging users to get a steady stream of ‘alpha and beta’ phase ‘updates’ that often break more things than they fix. Be careful what you wish for. I’d rather have less frequent updates that are well tested in large scale production environments than be forced to pay $40 a month or more for some kind of ‘subscription service’ to get a steady stream of ALPHA releases and broken new features (and a lot of advertisements and HYPE).
I do know of a few things buried DEEP inside Halion 5 that don’t ‘seem’ to work quite the way it’s documented in English (perhaps just a translation error in writing the manual)…but the behavior was still consistent and useable. I really had to go digging and making complex sounds to find such issues. Despite some of my misunderstandings over the learning curve of mastering the instrument, there have always been at least 3 other valid methods supported by the Halion engine to finish my patches/programs and achieve the desired sonic effect.
I do agree that Halion needs some refinement in how users can save, manage, and distribute custom content. It can and should be more user friendly, with more tools to refine and distribute new content (I.E. Make third party libraries supporting the Macro and scripting engines to share or sell). I’m pretty sure that IS coming in H6. I’m interested in these new tools, so I’ll buy it 
I have very little trouble getting Halion Engine products to WORK…and to work very well.
On my rig H5 and GA4 are very productive plugins AS IS. I easily got my $240 dollars worth out of H5 during the first 6 months of using it.