The major differences are simple.
V2 was a straight deck. It had one joker with a reveal or two on it, but that was it. Came in black, red and blue. The tuck box had a cutout in the back displaying the "LS" logo.
V1 was more of a magician's deck. Among the many hidden features was a one-way mark and a marking system to identify suit and value. The "LS" logo on the back is reversed so at a glance you can tell the difference between a V2 and a V1 of the same color. V1 came in red, blue and "metallic green" - it didn't look very metallic to me, more like a bit pale. No cutout on the back.
Both decks were made to the same high quality standards, using German black-core stock imported to the printer in Taipei. If you've never handled a deck from that factory before and have only used USPC all your life, you'll notice an immediate difference in the feel of the cards. The coating is unique and the cards are just this side of indestructible, especially compared to most of USPC's mass-produced output.