I've been using MOTU with windows since before Vista and I can honestly say absolutely no horror stories for 12 years. But - I keep my machine off the internet except to connect with Microsoft for OS updates, cakewalk or waves program updates. I haven't added any other software. None. Not sure what has been said negatively, which indeed may have merit, but I simply have not experienced it with my setup, work process or system load. I do not do much MIDI, I rarely use over 30 tracks, I record max at 96k, 24 bit. I don't add a lot of effects until mix down, and I rely on Quemix, now AVB routing so I play it safe on latency issues. With AVB mixing comes a whole slew of advantages when I have the gang over to record.
There was an extensive and long running forum chat out there from just before the AVB launch that had MOTU engineering popping in from time to time, and really laid out the specs, what was done and where the product was headed. For a company to release what was under the hood before launch, and even sharing some things that marketing would run for this hills - figuratively - piqued my interest early on. So far, everything that I recall which was important to me, has been implemented. I am waiting for win thunderbolt, but they have been honest on their support and direction.. I have USB2 and Ethernet, and that's good enough for now.
Your mileage may vary, but I really enjoy MOTU's latest flagship design, support, and direction.
Best Regards
LL