The price is low but you need to find out how many hours you'll be getting. Usually some of these courses lure people in with low prices and you end up taking a lot longer and paying more.
As far as doing an accelerated course, make sure you are instrument proficient and read up on all of the multiengine book stuff ( POH, aerodynamics, engines, Vmc, etc.) before you start the program.
I did mine at ATP and had all that stuff down before I began my training. In 3 days I flew 10 hours including the checkride for my Commercial ME-IFR rating.
I'd recommend ATP as an alternative. They charge a little more but their program is very good. Its very accelerated but doable if you study the guide they send you before training. The planes are in good shape and the training is well structured.
One other thing, for those of you who are skeptical of ATP, pilots do fail their ME rides at ATP. I've seen it happen a few times while I was down there. One guy didn't even get past the oral.