If you're not staying it's probably not a good plan to go ahead although some real estate agents will say it'll increase value. Don't believe it, it's not true, certainly not a reason to get it in the first place - trust me on that, I was one for twenty years. If it's there it can add some appeal and maybe a little value, but outlaying to (prospectively) add that value isn't a good idea.
There's rogues out here too, I did a lot of research and was super careful, but I've been very happy with mine.
It's a bit of a minefield really, here anyway, and needs to be approached with caution.
That's my thinking on both accounts. We have some commercials on TV lately about it, but all of them feel like used car salesmen. It just doesn't sit right with me. We had a huge tree removed a year or two ago and that now gives us direct sunlight on a portion of our house pretty much all day. I think if we were planning to stay, it would be worth tracking down a reputable company.