I'm a satisfied user of Toshiba SD-R5272 for several weeks now. I have burnt few dozens of DVDs and I can tell you this:
-It seems that NEC ND-2500A is slightly better in terms of writing quality. Nevertheless, Toshiba's writing is still very good.
-Toshiba is supposedly somewhat pickier when it comes to cheap media. I can't confirm that as I was using not-so-lousy (but still pretty cheap) Ritek and Ricoh media. Results are OK.
-Very fast reading (both DVD & CD media), while NEC is painfully slow
-Pretty good writing (not the best, but still very good)
-Very quiet during spin-ups & spin-downs, unlike most drives
-Unlike NEC, it CAN bypass almost every game protection scheme
-reads DVD-RAM format
All in all, NEC is a very good writer, but don't buy it if you don't have another DVD reader (a fast one) in your system. Toshiba, on the other hand, does everything well enough, great reader, good writer, fast, quiet... It is well suited to be an only drive in a system. I can recommend it!!!