I own a MOTU 8M and can tell you there is no competition in it's price range, period.
I needed to dump my buggy Windows firewire, (MOTU 8pre) and Windows users have limited options. I thought the 8pre was OK but it wasn't my first choice for anything critical, the MkIII units were a jump up from MkII and I was looking into saving a few bucks by going with a 896MkIII. I auditioned the Scarlett pro 40 and the pres sounded better than my 8pre, neither one is in the same league as the 8M which if not "pristine" are very usable for most of my needs. For those other times, well these units play very nicely with others. When my wallet recovers from the 8M I'm thinking of adding a Universal Audio 4-710d. Anyone with experience with this unit? The Thunderbolt equipped Clarett series looks nice but I doubt if windows implementation is even being talked about.
The 8m integrated easily with my system and Sonar X3. USB implementation is still an issue and thunderbolt is not forthcoming at this time. MOTU is currently working on getting more than 24 channels on USB, which is a limitation.
The 1248 employs the Cirrus CS5381 ADC and the 8M uses 2 Cirrus CS5361 ADC's per channel. The gain is 63db for the 1248 and 53db for the 8M. The difference being the employment of V-limiter circuitry. The DAC's used are the Sabre32 Ultra 8-channel DAC, which I believe you will find in gear costing much more. My biggest complaint is that I'm now hearing things that were not there before, bad things. The emperor indeed has no clothes, and there is nowhere to run, I have to up my game. Not that most of our current population of music consumers , who mostly listen to music on some device, could tell the difference.
Latency is 12.3ms using 96/24 and will run for as long as I need it to so far. Decreasing the buffer size results in bad things. 48/24 is 6ms if needed.
However lots of other units do around the same thing for around the same price, so what sets these units apart? AVB. You control your unit with a web ap from any networked device. Live mixing from you ipad anywhere in the hall? This starts putting ideas of bringing your unit out on the road. Build quality appears to be the same as most other MOTU units, all metal case, plastic front knobs. If that is you idea of cheap and plastic-y, no worries, it's just different than mine. Still would I take it out on the road? No, not at this time, but perhaps for a live recording in the future.
AVB uses ethernet and it is how you get your updates. I'm using Linux right now run it all . Not being platform dependent is sweet.
The software is wonderful, intuitive and has yet to crash. The DSP can be inserted where you wish taking a load off of your CPU and perhaps a bit better quality than what Sonar is offering (subjective). Routing has never been easier. It was literally open it up and start to use it. Using the ADAT banks you can link MOTU or other units. If you happen to be on the Mac side, you even get AVB audio interfacing and linking. For large facilities, teaching institutions and such it could come in very handy.