If you really want to make an educated decision, my suggestion would be to review the instruction booklet
for 6212 as well as the brick inventory
. Once 9493 comes out this January (or, more likely, mid-to-late December), you should be able to take a look at the instructions and inventory of that set using those same resources I linked to.
If you don't want to wait, just go with your gut or make a decision based on the available photos. Just keep in mind, 6212 might not be around for much longer...I would think it would still be available somewhere for MSRP in January, but don't expect it to be widely available after March or so of 2012. 6212 originally came out in 2006, so it already bucks the 2-year lifespan trend a lot of sets are subject to...but given the ship being represented and its popularity, it's not to surprising that they extended the production run. But, with a new version of the X-Wing to sell (9493), you can count on the existing stock of 6212 currently available at retailers being all that's left.
As an aside, you may want to check out the information in this thread
. It's good information to have if you're getting back into the hobby. I find your statement about "...just wanting to get some very specific sets" adorable.
Little did you know, my friend, it is likely already too late...you have taken the first step upon a very slippery slope that has led you here.