please don't start threads asking questions of the kind "is it worth it?". there are long threads concerning most dvd writers explaining more or less their advantages and disadvantages. in these threads there are links that can lead you to reviews of the drives made by well qualified people.
You made it posting in the forum, so I'm sure you have the experience to make a search in the forum to find the necessary info.
As for your question, you have to specify what you need the drive for. DVD writers at this moment cannot fully replace neither a CDRW, nor IMO a good DVD-ROM. The ND-1300a (I've never heard of 1300b) will allow you to burn in both formats and even make some sort of copies of your DVD movies. It wouldn't copy the latest data/audio protections though. I would say it is (almost) as good as any other DVD dual writer, only at a much better price
Try here for more info http://club.cdfreaks.com/showthread.php?s=&threadid=60975
I hope I helped you a bit. 280euros e? Where is that from, PLAISIO? I think I'm missing Greece too much
Na 'sai kala