I've got a few Memorex and they works fine, although one disc had bit of a sticky door on the cartridge. It's been fine since though. I have one double sided Pengo disc, and it works fine.
I've had no problems with Verbatim or TDK either. I haven't used Maxell or Panasonic, but they are supposed to work great.
Fortunately, it seems most of the DVD-RAM media out there is not bad. Even the off-brand ones seem to work fine according to almost every DVD-RAM media post I've seen. For instance, everybody states that they've had good results with Optodisc DVD-RAM, even though Optodisc DVD-R is dicey according to reports. (Optodisc DVD-RAM is Panasonic certified though.) One thing that does make me feel a bit better about cheaper DVD-RAM, is all DVD-RAM writes are always verified.