Basically they're two different structures that work the same in practice. Here's a link to everything you've ever wanted to know about the DVD format http://www.dvddemystified.com/dvdfaq.html
Let me just say all DVD players are not created equal.. Most newer models will recognize both formats, and I stress the word "most".
As explained in the previous sections, there are two main formats: "dash" (DVD-R/RW) and "plus" (DVD+R/RW). There's not much difference between them. They both record data and video, and they both read back data and play back video. Both formats are available as recordable drives for computers and as home video recorders. In spite of claims that one format is more compatible with players and drives, both formats are similarly compatible (see 4.3.1). There are speed differences, but it's a game of leapfrog. One format will come out with faster write speeds, then the other one will match it or surpass it. In 2003, drives reached 8x speeds. 16x is the theoretical maximum, so both formats will soon hit the limit. The biggest thing to worry about is that DVD-RW drives only record on -R and -RW discs, and DVD+RW drives only record on +R and +RW discs, so you have to make sure you get the right kind of blank discs. You may worry that one of the formats might "win" and the other format could disappear, leaving you with abandoned hardware. This is not very likely, since both formats are doing well. Luckily there is a simple solution to both concerns: buy a dual-format, or "combo" drive. Many companies make DVD-/+RW drives that write to both kinds of discs. Dual-format drives cost a bit more, but it's cheap insurance. The DVD+RW format has a few advantages when used in a computer, but if data backup or access speed is important, also consider the DVD-RAM format. DVD-RAM is fast and reliable, and the discs have an optional cartridge to help protect data. Most DVD-RAM drives also write DVD-R/RW discs, and some super combo drives write all three formats. [4.3.7] Other recordable optical formats
Hi there, Using the same media (Ridata G04). Using 2 different burners: LG-4040B (2x) and Philips DVD8631 (4x) The end results will not be the same on 2 DVD Players. I have a Toshiba that I payed $99.00can and I have an LG that I payed $169.00can. The toshiba is way more picky on what I burn. The LG, played anything and everthing I gave him. Moral of the story, sometimes DVD-R or DVD+R will only make a difference, on the quality of your DVD player. WalMart sells DVD Player for like $39.99 Then I've seen good DVD player at $209.00 There must be a quality difference in the laser... My 2 cents worth...
It has actually nothing to do with the laser, but with the bios chip in the DVD player.. Some of the newer models will even allow you to flash there firmware with a CD.. Thats the kind to look for that way you will never be out of date with what it will or wont read.