Cost, comparisons and tips
Many online retailers will do this "on contract" bringing the phone down to a FREE price point. Im sure google will help you find them. I got my M900 for £99 on 18months which is pretty standard for this sort of phone.
Support wise, so far i've been VERY impressed with Acer and lets be honest, its a brand new device so there will be issues. A fair few of us have been on 4winmobile.com logging our issues and Acer have activley been looking at this thread and others. I suspect we will see new firmware released VERY soon and we have already seen "lite" ROMS cooked. WinMo 6.5 is well underway.
It seems that most people dump the Acer Shell, some die hards still like windows today screen (?!) but a lot of us have put on SPB MS3 and its awesome .... really, really flies on the M900. Btw, if you don't use Acer Shell, delete the Shell and AcerShell directories from program files and you will have another 30 or 40 meg free... result! Having done this, and being a heavy user, I can honestly say i have never had memory issues. Numbers are an indicator, not a "be all, end all".
I am very puzzled though why you decided to review the mid-range and keep comparing it against HTC's top range when the M900 is clearly the top range of Acers. Kind of like putting an M3 against a Lambo..... not the fairest of decisions.