I used it and it does the job. It's handy if you're in a bind and definitely a lot less trouble than rooting...but overall the "built-in" feature of a rooted/custom rom phone is a helluva lot easier to use. If you aren't going to use it often or don't feel comfortable rooting/flashing, then it's just what you need.
Is it really in the marketplace? Last time I used it, it wasn't, and I had to download from PDANet's site, copy to the phone through USB, then install... Marketplaces are different for each carrier, so maybe some don't have it removed.