Well i know if i tried to build 1 myself i'd **** it up somehow - at least buying built with OS installed i have a 1 year warranty so can take it back if anything goes wrong.
The system worked out a lot cheaper than CCL who i thought were the cheapest local (ish)
Hopefully it'll last me a good few years without having to upgrade it? - just hope it's ready for collection on saturday as i asked for (he hasn't acknowledged my last email)