I've used the Wyeast (2352) and Omega (Bayren Lager) versions of L17 Harvest before, and I've only had good experiences with Imperial's comparable strains. Supposedly, this specific strain is the lager strain from Augustiner brewery in Munich.
L17 should work VERY well in both of the styles you mentioned. I actually developed one of my Marzen recipes around this yeast strain, and have no doubt that it would work in a Vienna just as well.
It's a very clean fermenter, has a very neutral character, and flocculates better than the 2124 strain. It doesn't attenuate quite as much, and will leave the beer with ever so slightly more body. Definitely one of my favorite lager strains, and I need to get back to using it again.