The longer you record the lower the bitrate used the lower the quality. I personally find 6 hours mode unwatchable and widescreen signalling is switched off in extended recording modes. DVD+RW has the advantage of not having to be finalized in order to take it and play it on another player. DVD-RW has to be finalized to play it on another player (Except some Pioneer models). Finalizing can take some time depending on how much you recorded onto the disc.
I personally have a Pioneer DVD-R/RW and am very happy with it. It was a little more than something like a LiteOn but has features like chase play (Record and playback at the same time which can be handy for time shifting) and generally gives a better quality image than 'budget' brands.