Went through this sort of thing myself, recently.
My wife & I recently moved into a new house - and I noticed that using the wireless in the living room (the AP is upstairs in the spare bedroom I'm using as an office) could cause 30+ second outages at random.
Since I'd changed ISP, and therefore was using a different access point, I switched back to the MIMO one first as a check. This improved "peak" speed a little, but the dropouts still occured - seemingly as often.
Since I want to stream video over the house network (MythTV if you're interested) this wasn't an option - and after similar thoughts to those mentioned, I decided to go with the devolo powerline (85Mbps) answer.
I now have the MIMO AP in the living room, connected to the stuff in the office via the devolo. No more dropouts on the wireless, and the speed is pretty good. The devolo are reporting that they are linked to each other at around 85Mbps, and I can easily get a sustained 20Mbps from my laptop, via the AP and the devolo, to the machines in the office.
As pointed out in the article, I've got the issue now that I'm using 2 APs on 2 channels, which may make things worse for the wireless side, but thankfully around us there are a few channels still not in use....