heffer,
i would recommend the X1 for several reasons.
first of all, it is the best value anywhere in a 1/8 buggy. the quality and finish of the parts are unparalleled by any company.
check the race record of the jammin, it is very respectable for its short time out so far, compared obviously to that of Mugen/Kyosho.
Jammin parts are going to be cheaper than Losi parts generally, and should be easier to find.
although the 8ight is a new innovative design and experts say that it handles well with the stock box setup, what happens when you want to change that setup? well, this is where the X1 shines. any adjustment you make to the X1 you will immediately notice. and unlike a 777, you can do well with a close to perfect setup with the X1.