Since it is almost always a good idea to completely disassemble and rebuild the car when buying used, you can clean the parts (if necessary), check them for signs of wear (and if necessary, replace them), learn how to build and repair the car, and most importantly: make sure it is built correctly (which, unfortunately, is not a given).

But buying used is not for everyone - for all kinds of reasons. While I do not explicitly recommend it to new people in our club, I tell them to at least consider it - while giving them the advantages and possible disadvantages (and we all offer them help to check deals on used cars as well). Personally I generally do not buy used RC stuff - with very few exceptions (with people I know personally, and know how they drive and care for their stuff, I might make an exception.)

So if a used Xray (or other top brand car) isn't what you want, and you are sure you don't want to pony up some more money up front (upgrading the low budget kits is more expensive than getting the full car in the beginning - and buying cheap often is not cheaper in the long run... but most of us have been through that at some point), then I would probably go for the Xpress over the Sakura as well.