I just had a sub thread on a couple of sites, I'll give you the summary - if you can afford the Hsu, go with it.
The Hsu is a known entity and is very good. The Lava's claim to fame is it's price point. But there are very few reviews out yet on sound and build quality. But you can pretty much assume that the best you're going to get is Hsu performance at a discount. So why gamble if you have the funds.
For myself, I wanted to get the Hsu, considered the Lava but decided against it due to lack of data, and went with a Velodyne that was $60 cheaper than the Hsu. It's a Christmas present, so it hasn't been set up yet and I can't comment on build or pSUBMITerformance.