Ive got a Sire V7 5, first Gen. Cant comment on the V3. Very nice bass, plays really well and although i dont use the preamp much, its a good one. I believe most of the necks are the same throughout the first Gen, and its a very playable neck. One of the nicest ive owned, although a bit chunky. The newer Gen 2 necks are really, really nice though.
I also have a 425. Lovely bass. Feels basic but comfortable. It's not the same as a 435 (which I'm also after), so cant really comment on that either, but given the choice, I'd go for the basic passive option.