With the Roughstack you can only go 40 mph, with the maxi Roughstack you can go 40, 50, & 60 with the vaporluxe you can hit all the numbers in between.
The Roughstack V2 is limited to 3.7 volts. The Roughstack Maxi is larger and able to accommodate different batts for 3.7V-6V & 7.4 V vaping. I would prefer the vaporluxe since you can adjust the voltage without having to buy a lot of different batts. But for the $150 pricetag I would recommend the Provari or you can pick up a Lavatube kit for $100.
I do not have any of the units you are looking at so I can't say whether they are good or not.