[UI] the interface for firebird is awesome. there are several skins to choose from and they are all very well done. a LOT of attention to detail and TLC went into the UI. the simplicity of layout and the beautiful tactile feel of the controls is really great. the setup screen is dead simple and it's very easy to use this synth to achieve great sounds quickly. everything important is on one screen and all of the complexity is hidden away from you leaving you only to worry about your sound (the way it should be IMO). the only slightly confusing thing is how the modulation wheel mapping is in the setup screen. it's odd only because setup is usually a global thing, but in firebird there are patch based settings in the setup screen. not a deal breaker for me though at all :)
[SOUND] firebird sounds incredible. it's got some huge sounding filters and the distortion / drive is particularly awesome. the sheer number of filter types on offer is quite insane - but coming from tone2 we expect nothing less than greatness. the various waveforms available are versatile and cover a very wide variety of sound creation possibility and it's simple to quickly change and sculpt the sound by combining them in different ways. my *favorite* part of this synth is the FAT and ANALOG knobs in the sound source section, simply twisting these two at various degrees (which are obviously tuned with TLC to really be useful) is so much fun. you can alter the brightness, tone, and thickness of the sounds to be much more intense as needed, or back it off (which i find myself doing more of because firebird has so much balls) to make things fit more into a given mix.
[FEATURES] the features available are very good and easy to use. there are all the staple features you'd expect from a great synth and a few you wouldn't like an advanced IQ micro-tuning system that actually makes a significant difference to the sound output. it's this kind of attention to detail that firebird has all over. there are governors for polyphony and quality for machines that are older or slower as well. i have 0 complaints about the features. Markus (the developer) even added a feature that I requested to allow for my inacurate pitchbend to work better.
[DOCUMENTATION] the documentation is adequate. i didn't really need it though. it's available in 3 different languages, which is nice.
[PRESETS] the factory banks (3 of 128 each) are awesome. the 3rd bank is a nice touch as it is the "init" bank so you can roll your own sound bank with ease. bank A and B have some excellent sounds for electronic music. really good ones that illustrate what this synth can do. the sounds range in category from bass to lead to pad to others and are useful and organized by prefix so it's a snap to dial in a sound you are looking for without hunting around too much. i've already mentioned the fat and analog knobs but i need to mention them again because with those 2 knobs every preset gets a new life. the randomizer is quite a cool feature too that is built into firebird and 90% of the time provides something new and interesting and somewhat useful.
[SUPPORT] customer support from tone2 in my experience has been great. i've not had any issues with the synth besides the one i mentioned with my pitchbender and that was addressed in v1.9 after almost 3 months of no word from the developer it was quite cool to get a personal email announcing the availability of the new version with that support added in. it was an excellent gift and will keep me a customer of tone2 for a long time to come.
[VALUE FOR MONEY] the cost for this synth is €59, $79 which is a total value in my opinion for what you get. after spending quality time with this synth you can tell that a huge amount of effort and insight went into it's plans. the price is fully justified and then some. well worth the outlay.
[STABILITY] i've had no issue with firebird in the following hosts: cantabile 1.2, orion platinum 7, tracktion3, energyxt 1.x, ableton live6, flstudio 7, and renoise. i have not used firebird in an extreme scenario yet though, mainly i use it for bass and lead sounds to compliment other synths when doing electronic music.
[SUMMARY] if you need a good synth with very high quality sounds for a modest price you can do a hell of a lot worse than firebird. if you are new and want to learn about synths and how to program sounds firebird is an excellent choice as it's so damned easy to use and easy to get a good sound out of. it is very encouraging to design sounds when the sound coming out is beautiful to your ears.