BFL is shipping units now but they are are still backed up and have yet to ship out many orders.
Avalon has sold all their 3 batches of units. #2 is partially shipped and #3 has yet to be fulfilled. They are now selling chips to assemblers and endusers.
ASICMINER has their blades and USB's for sale with quick turnaround but they are known to be overpriced.
All other manufacturers have yet to ship out a production unit. They are still in development and most are taking or have taken preorders. Hope this helps.
Just like to add ASICMINER are basically an in-house mining outfit that have recently offered hardware to the public as a "sideline". Shareholders in ASICMINER profit from both sides of the business.
If you really have to mine yourself, I would steer clear of their current offerings for sure, even though the USB miner has just halved in price. If you want to profit from mining, that's a completely different set of criteria, as ASICMINER currently mine with their own equipment 20% to 25% of all bitcoins mined. That excludes all the bitcoins produced through USB and blade mining equipment sold to the public.
You can get direct shares in their mining operation by auctions that pop-up or buy pass-through shares at places like:
https://btct.co/security/ASICMINER-PT
