Haven't tried it yet. Still a bit too pricey for me. I was looking into the NEC ND-2510, which is an 8x dual-format single layer burner with 2.4x DVD+R DL capabilities. That's on Newegg right now for only $92 shipped. I'm a bigger fan of NEC for DVD burners than Sony, Pioneer, etc. Soon as my next check comes through, I'll get back to you on that one.
The big thing is DL burning is in its infancy right now, with compatibility reports ranging from 40-80% depending who you ask. Not to mention there's literally ZERO blank DL media out yet. I've heard that you really should wait til the second generation DL burners before jumping in. I was just about to get a NEC ND-2500 (same as above, with no DL) for $75 anyways when I saw the 2510 come out. For less than $20 difference, I'll probably go for the 2510 with DL anyways and hope NEC stays on top of firmware.
As for DVDA2, it doesn't do dual-layer. Hopefully we'll see an update for this, but I'm not holding my breath for it coming anytime soon. We can dream, can't we?
I wouldn't rush out to buy one, mainly becasue the media won't even be readily available to near the end of this year. I'm waiting for the Pioneer A-09 myself, I find the Pioneer's to be much more solid drives.