Okay, I'm about to say something very un-FT'er like.

For a six-month stay, I'd evaluate neighborhoods first, specific hotel properties second, and rewards programs third. If somebody told me I had to live in the Twin Cities for six months - and I really enjoy the Twin Cities - there is no way I'd live in the Eagan/Airport/Mall area unless I absolutely had to. A great rewards program is nice, but not if you have to spend six months in a depressing place to score about two free weeks at a resort later. Nothing against Eagan per se: but airport hotels the world over are lifeless, depressing places. I've hit most of those properties near MSP at one point or another - they are no exception. I actually book those Residence Inns along that corridor 2-3 times a year because of the 2-bedroom suites, but there's no way I'd solo there.

For my first week, I'd do three or four 1-night samples in different properties around the MSP area. I'd probably pick 2-3 neighborhoods within a reasonable commute of your work site. I'd probably drive around a lot - check out a few restaurants, go for evening runs in different parts of town, etc. Then narrow it down from there. Figure out where you'll enjoy your time there. The Twin Cities is a full of character and has a surprising level of funkiness - especially in the summer!

Other brands to consider are Homewood and Hyatt Place (I assume they have those in the Cities...). Hilton Diamonds generally seem like a happy bunch. Homewoods tend to price competitively with RI. Don't know much about Hyatt Place other than it's a new brand and Hyatt is running some promos to drive traffic to its extended-stay brands.