Largo

It's interesting that this is my first review for KVR, as I own and frequently use a bunch of soft synths, but Largo really impressed me. It's got oodles of character, nearly unlimited options for sound design, some of the best (software) filters around, and manages to be fairly unique in a field where it's hard for products to stand out from the crowd.

User Interface:
Largo looks great – it's got a very sleek, professional, metallic look that's unobtrusive and easy-on-the-eye. I also feel that the look reflects the character of the synth well. The layout follows the typical soft synth workflow – Oscillators to the left, filters to the right, modulations and FX at the bottom. While I enjoy working with this UI, there are some awkward points to it: first off, it's a little sluggish. There's a bit of lag when turning knobs, switching windows, and adjusting values. I found the decision to make some knobs smaller/larger than others a bit counter-intuitive in places. The mod matrix is a tad too small when compared to the rest – I found myself squinting a bit when I used it. Lastly, it's a mixture of knobs and numerical values, which is a tepid compromise, if serviceable. Overall, though, I found that working with this interface is fun and fast.

Sound:
The most important part, right? Well, there's been some controversy regarding the sound of Largo. Some hate it, some love it. And then there's those who'll contend that any synth that is capable of deep sound design doesn't have a "sound" - they claim it's up the user. I belong in the camp of believers in a synth's character. Largo is definitely special. Starting with the Oscillators, which offer the usual, plus a load of high-quality wavetables – a Waldorf trademark (AFAIK, all the PPG and Q tables are there). These raw materials already sound great by themselves and will keep you entertained for quite a while. Get to the filters, though, and Largo really begins to shine. They have a real bite to them, and the resonance can wreak some splendid havoc on your sounds. There are 8 drive types for the filters (I think the Blofeld has more, but maybe they'll update it at some point) which can add subtle to all-out distortion to your sound. The bass boost is there, as well - a lot of Largo's power in this area comes from this innocuous button. The effects sound great, as well. While many synths feature unison, I was quite unprepared for what would happen when I switched it on in Largo – the sound grew in density in a way that left me speechless. "Huge" does not begin to describe it.
Overall, I love the sound of Largo – it's very much got a digital quality, but it can be anything from warm to cold, biting to soft, or grimy to clean. It's actually very easy to steer it into down-n-dirty territory, so if that's your cup of tea, you really should give it a go. This synth can really GROWL, but it can purr just as well.

Features:
You can read about these in the specs on Waldorf's website, but I'll mention a few things that caught my eye: Largo offers 4-way multitimbrality. That's 4 synths in one. Yes, you can layer your synths in your host, no problem, but for sound design purposes, this is quite a boon. Each layer has three oscillators, two of which feature full wavetable compatibility and a sub osc. You have ring mod, FM, and sync at your disposal, and your oscillators can be freely routed to the two filters, which can function either in serial or parallel mode. There's a big mod matrix that also features some simple mathematical procedures like "add", "subtract", "and/or" etc... - there are a handful of modular synths that are naturally more flexible in this regard, but I think that Largo has more than enough potential here. 3 LFOs, 4 envelopes, a neat arpeggiator and an FX section (chorus, flanger, phaser, delay, overdrive and reverb) round it up. Honorable mention goes to the envelopes – these are among the best I've used on a soft synth. They offer an advanced ADSR, one-shot and loop functionality, and the attack is lightning-quick.
The UI also features a few sliders for often-used functions, like FM and wave amount – so you don't have to use the mod matrix for every single tweak, which is a nice touch.
Two gripes: setting up the arpeggiator is a bit fiddly. It would also be nice to be able to save your settings.
Bottom line: there are huge possibilities for sound design.

Docs:
...are there in English and German. Short and to the point, with some humor thrown in for good measure. There are also quite a few neat tips and tricks in there, so it's really worth checking out.

Presets:
Largo currently offers over 700 presets. They're well-hidden in the unnecessarily obfuscated browser, which could so with an update. They do a good job of showing the synth's capabilities, and are of a high quality throughout. I especially like the soundscape/atmosphere-type of sounds. Although I rarely use presets, some of these are very inspiring.

Customer Support:
I have never had to use it, so no comment here.

Value for money:
This is always hard to judge. There are a few synths that have similar specs and are cheaper. I will still give this a high rank, though, simply because Largo is unique – I can get sounds out of it that are simply not possible with my other synths. It's one of a select few that can easily inspire me – and cranking those filters into the red zone gives me goosebumps every time. So, yeah, definitely worth it.

Stability: Granite-solid in Live 8.2.1 and Reaper.

Two more remarks in closing: I evaluated Largo for a month before making my decision (which, btw, is a very generous, uncrippled demo period). I didn't really feel that I needed yet another synth. In the end, though, I was utterly convinced. And lastly, I have to point out that this synth can really tax your cpu. If you don't own a fairly modern computer, you might get into snap, crackle and pop territory faster than you'd like, so demo it before you buy.