I have no clue on the build or overall performance of the LavaTube, but if the price is even close to that of the IPro, the IPro has a solid pedigree.
I like the IPro due to its performance, run time between charges, durability, ease of use (just the simple voltage adjust wheel, and unscrew the bottom cap slightly for a positive "off"), well known quality customer service, and excellent price compared to the Provari or other higher end VV/VP.
Provari is a shrug to me. It has a loyal following, undoubtedly deserved. Provari has a screen (not something I care about, and people have had to do replacements on them -- even if under warranty, your PV is gone while it goes to the shop), a multi-click user interface (sounds like a PITA, but that's just me), not sure about the battery life unless you go to the plus-sized batteries with extenders, is generally heavy (from what I've been told), noticeably higher price point (any PV should be fully kitted out, with a couple sets of batteries, charger, to do a price comparison). Whether something is a feature or a hindrance depends on what a user wants in a PV, truly subjective. I'm sure the screen adds to price, so if you want it it is worth it; in my case I don't care about the precise voltage readout, or being able to check atty resistance on the run. People I know and respect do own Provaris, just wasn't for me.