I find that I am able to keep my little sewing machine drawer on the table next to me (not on the extension table, just on my regular table), and use it that way. If your machine drawer isn't such that you can do this, and you don't have another container to use, or don't want it in a different container, then the accessory drawer on the extension table might be the way to go.
For me, the budget was better spent on the larger size (the size I wanted didn't come with a drawer, and was both larger and cheaper than the one with the drawer), and then using a simple box on the side of my table works well. I might get a small clear box from a craft store and just place it under my extension table, but for now this is fine.
LOVE the ease of quilting with the extension table in place, and even piecing borders, etc. So nice!
In the reviews I read, they mostly said not to worry over the drawer, etc, unless that's a particular feature you want/need.
As far as size, I wanted the biggest I could get, but did remember I need to measure my actual table as well, so quite literally got the largest size that would fit where my sewing machine is. My table is long but narrow, so I couldn't get the 24" x 36" one, but got the next size down, with no accessories (via Amazon) so it was something like $108. I've received it but not opened it yet, as it's my Christmas gift....
I figured I could add rulers and things later on if I want, and there are TONS of sources for those, no need to lump them into this purchase when, for me, it was already stretching the Christmas budget (and I wanted room left to get the Machingers gloves and the straight stitch plate for my machine....). I'd say the accessories are up to you, what you think you'll use/need/want.
For ex, I never access my tool drawer while sewing, because I have a separate bobbin box (and I get out alternate feet ahead of time, if I'm going to need them, etc.) and if I need to, mine is on front of my machine so I think I'll be able to reach under and get into it if needed. If I normally was in & out of my drawer all the time, and it was going to be blocked, I'd have made that a higher priority -- does that make sense?