I've used it for a couple of beers and found no banana or clove character at all. It's intended to be a very, very clean ale yeast, with perhaps a bit of fruitiness, but I've never thought of Kölsches as having "banana" flavors.
It's a bit of a specialty yeast, though, and does require fairly careful temperature control. For a Kölsch yeast, it tolerates relatively high temperatures, but you really want to keep it in the mid-to-low 60s during the active fermentation to avoid the center of the fermenter running up in to the 70s. It might produce some of the off flavors if the temperature runs high.
Also, as I've now said three times, it's intended for Kölsch brewing. This traditionally involves a month-long or longer lagering after fermentation completes, which helps to achieve the clean lager-like character of the hybrid ale style. I've always (both times) done a month at about 40°F so I can't say first-hand what effect it has, except that my beers came out great. The manufacturer quite firmly recommends this step. With this step, I got two almost completely sediment-free beers. I've heard reports of flocculation problems, though, so I suspect that the lagering is important to achieving this.
http://www.whitelabs.com/beer/strains_wlp029.html
I used it for my third beer, but I had also fermented a mead and a cider in between, the mead in particular which required some relatively close attention to the process. It worked out quite well for me, but I don't know that this is necessarily the best choice if you're not confident in your techniques. You want to be sure you can control your temperatures, and you would be advised to make a starter with this (or most) liquid yeasts. That's not hard, but it's additional steps. (I don't mean to put you off the idea, just giving you my thoughts.)