We've had one for a couple of years...it works well for keeping our big addition cool (the part we have the most trouble with - not so much since we took out the 3 big south-facing windows and re-insulated the outside of the house before siding). But keeping it cool in there keeps the rest of the house at a decent temperature, lol.
A couple things I don't like are that it has to hook up to a window that opens - making that window unusable for the whole summer (unless you like hooking it all back up again every time), and they're usually pretty big so it takes up a bit of room. In our house it sits in a very odd place but it's just because that's where the window is. We also don't have a place to put it in the winter right now (our storage room is full of tools from the renovations we're doing) so it sits there year round, lol.
But yeah, it works pretty good. We have a small one for the kitchen as well, that just fits right in the window. Of course, we got new windows and found out afterwards that our new a/c wouldn't fit in it properly because of a lip...but it was too late, so we have to kindof balance it in there with a rolled up towel underneath...too much and it'll fall out the window to the outside, not enough and it slides into our sink. LOL...good times.
Really though, if you can't afford central a/c, a portable is a good option. They're still pricey and you HAVE to get them early in the season before the first really hot spell or stores will be sold out, lol.
