There are no stupid questions, only stupid people (jk)
Meritline sells pretty decent cheap DVD-R/RW's - see the link above. Of course, with the generic stuff, YMMV - but so far, I've had very good success (with the exception of a Toshiba set top box, it's worked in 5 other players).
As far as your speed question - it's limited in recording only.
For those that don't remember the early days of CD-R, let me fill you in - it was JUST like this. Earlier on, media was expensive, and generic media was pretty shoddy. You could record at 2 or 4x with 'certified' media, and uncertified media yielded all kinds of crazy results. In fact - the early goings of DVD-R/RW are MUCH better, considering the existence of buffer underrun protection. Don't want to know how many $10 coasters I made back in the days of 'fast (read - 4x) CD-R burning.
Pioneer makes excellent media - and in an attempt to save you money, let's you write to generic media just fine - just keeps the drive from writing at 2x. The difference - about half an hour. The actual difference - not much, because since the media isn't CD-R cheap, you're more than likely not going to crank out 25 DVD's an hour.
The dual-layer bit - check Doom9 - plenty of people do something to get around the whole dual layer issue, and it works out just fine in most cases.
Like I did with CD-R, I supported Pioneer for bringing an excellent product to market in face of some pretty serious (and only detrimental) competition. The remaining players - Sony, HP, Philips - all had vested interests in why they didn't want you to have cheaply available DVD rewriteable media and players (think RIAA and MPAA), and introduced their offerings mostly to fragment the market. For depriving us of our legal rights to back up media that belongs to us (and it *is* a legally established right, provided you own the original) - and for shoving the DMCA down our throats courtesy of strong lobbyists, I say 'Thanks Pioneer!'.