I love my Arthurian! I recently acquired the purple book with all the exercises etc to work through with it, though I haven't got started with it yet (99p on ebay what a bargain!).
I have 2 different editions of the deck, each with black borders so I can't comment on the white bordered version. I love this deck for meditating with. The pip cards feature scenery of the British isles, and they are people free so you can 'enter' the card in your meditation and just enjoy the peace and quiet. I have to confess that is the main thing I use it for, I rarely read the cards for divination. It has a permanent place by my bedside though, and there aren't many of my decks that have that priveledge.
I'm fairly new to Tarot so I missed out on the Arthurian theme decks phase. I just like the deck for the imagery, I'm not familiar with Arthurian mythology in any great detail, or the grail mysteries.
I have to say though I do like the black borders, it makes me feel much more like I am looking through a doorway into the snapshot scene on the card. I don't think I would get the same effect if the border was white