The u2 presales worked like a charm for me, unlike may others, but the citi pre-sales were a bust. I got the pull down for citi pre-sales promptly at 9 am, but whatever tickets I requested, in whatever category including "best available", or number, returned an error message asking me to try again later. No message that there were no tickets available, just an error message with the search. If others were able to get in, I'm assuming the allocation is probably gone by now. Oh well.