I've been offered a Blade II at an ok price and was wondering if there's a significant jump (pardon the pun) between it and the current blades?

There are a few little tweaks to the latest blades from what I've read but nothing huge. The main one being from the triple A adjuster (Adjustable Angle of Attack) giving you more options to match your wind conditions.

Interestingly, cell number has decreased by 1 since the early Blades. Cell number keeps the aerofoil shape accurately defined for more power but this may be redundant due to internal V shaped ribs on newer versions.
The aspect ratio has also been lowered. The Blade II AR = 5.2 which is more than some race kites! This gives the kite its power and lift and probably why the Blade II was known as the widow maker. It was also the only kite ever to have sent me to hospital and I hope the last.

I've not flown the anything above Mk3 except the Flexifoil Blurr with its Triple A, so I can't give you a compassion. The MkII is or was seen as the ultimate powerhouse Blade amongst purists but that might be nostalgia. It really was a hooligan though.

I flew the MkII for 10 years and I still have very fond memories of it and anyone still using it today for buggying would definitely get my respect.

Blade II = Raw power

Blade V = Refined power

What size? What is your previous experience? What do you want to do with it? What is your average wind?

I have been revisiting and as always, really enjoying my 9m Blade II this past weekend. A friend was on his 7m yesterday. Both served up pretty well for old tech and the poor pilots we both are. I got the $200 I invested in that kite back about 8 years ago and it still makes me smile! It served as an engine today when my 18m Phantom wasn't quite cutting it.

The Blade II that got the nickname widow maker was the 4.9m I think. It had tons of lift but it had a tendency to boost you big and then drop you like a rock. I use my big Blade as a low wind engine and in that way it has pleased me consistantly. It is slow turning so I struggle using it for jumping. It's range is a bit small but it gets me going in some pretty low winds. It is a gentle giant and has never turned on me like the faster smaller ones can. Like my 10.8 Reactor did a couple of times.

Condition is important with an older model like that. The material can get really soft + leaky. Kite refit coating worked great on mine!