I had just read THG review of top DVD burners and the conclusion for video burning is that DVD+R are more 'flexible' than DVD-R. What makes it to be so, if all latest standalones support both +/- format?

In theory, DVD+R is better for recording video for playback on a standalone player since it includes technology to make sure that when the laser turns off and back on it is in the same spot. Depending on how you burn DVD's this may or may not apply. Besides that there are slightly more standalones that can read DVD+R than DVD-R. If you want to check a particular model try www.vcdhelp.com. They have a searchable database of players built from user submissions and you can look up specific features and compatibility there.

If you want better information in general, you should go to www.afterdawn.com, which is where I learned everything I needed to know about DVD burners. They have discussion boards where you can get a lot of expert help. Just make sure you read the forum rules before you post anything there.