I've owned a Lavatube and now own a Provari and I can tell you it is night and day between the devices. I had issues with my Lavatube's button, it would require quite a lot of force to get the LT to fire (well past the audible click). I disliked how the buttons would rattle and also that the 510 connection was crooked, the batteries that came with the kit had a horrible life span (4-5 hours of light vaping @ 4.5v) for 1600mah "AW IMR" batteries (which by the way were generic flat tops with no markings and are certainly not AW IMR), overall the device just felt cheap. The Lavatube would also drain these batteries down to 2.6v before ceasing to function! This will surely shorten the lifespan of your batteries if you are not keeping an eye on the voltage. The Lavatube does not hold a constant voltage, if you set it to 4.5volts you get 4.31v ,4.26v ,4.10v ,4.02v and it keeps dropping, it also does not act well with Dual Coil Carto's, it doesn't matter what you set the voltage to you get some pitiful amount in the 3.3v range.
The Provari is built like a tank, and from what I've read/seen it seems to last forever (and hold its value 2nd hand). Heavier and smaller than the LT and the AW IMR 18490's that came with it seem to last me over a full day of vaping. The fit and finish is impeccable and the menu system is extremely easy to use. If you set 4.5volts on the Provari you get ... 4.5volts, and it doesn't move from there, a constant voltage to me just increases the quality of the vape (there is no variation). The Provari will also fire Dual Coil Cartomizers properly.
Basically in life you get what you pay for.
Would you rather own 4 Honda Civics or a Ferrari F-430...
As long as you have the funds without putting yourself in debt or having to put off important things like rent / food I'd say go for it. After owning a Provari, I do regret purchasing the Lavatube in the first place.
Just my

anyway, your mileage may vary.