My 2 cents:
Intro
I actually purchased the DVR-104 a week and a half ago from Jazz for about 30 bucks more than the Geeks have it for. I got the OEM version and there were a couple of reasons for my purchase. First off, the 104 is identical to the A04 retail box but of course minus the software. I'm not sure what the geeks will give you for s/w but Jazz gave me a CD for burning data etc but I forgot the title b/c I haven't installed yet. One of the inspirations for my purchase of the DVR-104 was from the fact that my iMac 800 G4 includes the very same drive and I absolutely loved the output. I also owned an HP DVD100i which you now see going for around 300 bucks or so (uses the DVD+RW spec). So for those who don't know, there are basically 3 major specs - DVD-RAM (fading), DVD-R/RW, and DVD+R/RW. i won't go into details about the drives
Stuff and observations
In any case, since I've used both the DVD+R/DVD+RW and the DVD-R/DVD-RW drives, these are my personal observations. Making a choice between DVD-R/RW vs DVD+R/RW will really depend on what you want in the long run though. There are tradeoffs to both standards.
[*]DVD+R/RW have faster burn rates mostly because of their slightly better technical specs and their method of burning.
[*]DVD-R/RW drives offer more compatiblity to today's current crop of set top DVD players but DVD+RW should gain more traction as time goes by.
[*]cheap priced DVD authoring sacrifices A LOT at least on the PC side. If you want to do some serious authoring work, you're really not going to get from products like MyDVD etc. Unfortunately Apple did get it right with iDVD.
[*]DVD-R media is slightly cheaper than the current crop of DVD+RW disks but that will probably equalize once the DVD+R disks come out
[*]AND an important note: The current first generation DVD+RW drives DO NOT support the DVD+R spec. Almost all of the DVD+RW drives out now (including the DVD100i from HP) is based on a Ricoh drive. If you want to burn DVD+R disks, which should provide more compatibility, you will have to wait for the 2nd gen DVD+R/RW drives in May
So my original DVD burner was the HP DVD100i. The drive itself is great for backup purposes of large data files etc. The speed that it burns at is I believe DVD 2.4X (forgot right now). Pretty darn fast. However, i soon discovered that a number of my DVD drives in my home systems could not read DVD+RW disks. There are ways to work around this but unfortunately these are little hacks you would have to do to your disks (changing a bit flag on the DVD+RW disk headers). Also to top all of this off, almost NONE of the set top DVD players I used could read my DVD+RW video disks. The only one that could fairly reliably read my DVD+RW disk was the XBox.
Now for the DVD-R stuff, once I got the iMac w/ the SuperDrive (basically a DVR-104), I was authoring disks that were played on nearly all of my systems and set top dvd players. The iDVD app is great but I wanted more control of my authoring system and also wanted something for the PC, so I went and purchased an IDE DVR-104 for my XP box.
Of course, you must remember that the DVD-R spec has been out a bit longer and thus more devices will be able to read the media. DVD+RW will undoubtedly gain more support as time passes but for the here and now if you want compatibility, then DVD-R drives are the way to go. If you don't care about compatiblility but you want speed in burning and you want to back up a lot of data fast, then perhaps a DVD+RW drive is better for you. Even with that, I would personally then wait for the 2nd gen drives coming out next month.
My Conclusions
So what is the verdict? It depends on what you want to do. I currently use Nero 5.5 to burn data and to copy DVDs etc. I use DVDIt! PE to do my DVD authoring. The current version of DVDIt! will support both DVD-R/RW and DVD+R/RW spec drives. DVR-104 has buffer underun support as well as the DVD100i drive. Both are capable of creating dvd videos. DVR-104 creating DVD-R based videos offer the better compatiblity in the here and now. They also have a wider audience of users than the DVD+RW folks. But this can all change in the long run so if you're not sure if you need a DVD burner, then wait. If you absolutely must have one, then make your choices based on your needs. Good luck.
Useful sites
For those wondering about compatibility since the current SuperDrive on the iMac 800 (and probably other Apple G4 systems) use the DVR-104, check out the apple compatiblility page for DVD-R:
Apple DVD-R Compatibility list
For the DVD+RW camp, check out:
Set top DVD player compatiblity list
and
DVD+RW DVD ROM compatibility list
Hope this helps anyone out there