Regardless of all the FUD being generated about BFL you will eventually get something that resembles what you ordered a lot later than you thought you would get it.

If you want to mine then don't let anyone stop you.  Its a free world and you can do what you want.  Besides, Bitcoin needs as many miners as it can get its hands on right now.

With that being said, do not waste your time with pre-orders until you have some experience.  There is plenty of decent hardware "in hand" out there available for purchase at a decent price.