the XB8 is the nicest kit i've built & i'm going to try it as my main bugy for next year
the 777SP1 i tried last year is also a very nice kit to build & the car has way more steering than anything else out there! the Kyosho looks like it will be stronger than the XRAY in a couple of areas but BOTH of these are Top kits!
i only did a few meetings with my 777 & found it a bit twitchy & it didn't feel planted on the track, i've only tried my XB8 briefly & although it doesn't have the agressive (too agressive most of the time) steering of the 777 it did feel a bit more stable
so i'll find out for sure once we start racing properly again!
if you like the MBX5 you'll love the XB8 as its quite similar in design & build only better & has better steering & is probably stronger with the C Hub fron end! its also got more adjustments than any other car on the market so it should be possible to tune for any eventuality