I have Vorti's on my Z4. Wear rate is pretty good. I've had the fronts on for about 3 years. I do around 8k miles a year and they have 3.5mm left on them. The rears take a hammering but hold up well.
If that's your only options, then definitely go for the Vorti's. The rain sports get a good write up, but I don't think they're in the same league.