
The 650V is on the left, the 750V is on the right.
As you can see from the photo, the drills themselves look identical, and there is very little difference to tell them apart visually.
The 650V has a Hammer Stop and a Hammer Action
The 760V has Hammer Stop, Hammer AND Rotation Stop
This means that only the 750V can be used with SDS Chisel Bits
Both feature the same Drill 'Housing' and features, so both have a level built in that lets you know when you are drill level and also lets you know when you are drilling perfectly vertically - a neat idea!
The 650V does not come with any accessories at all other then the carry case
The 750V comes with the same carry case, plus 3 SDS Drill Bits, a Chisel Bit and a Chuck converter that will let you use ordinary drill bits with the SDS drill - These accessories are probably worth about £15 or so at least I would have thought.
Both Drills seem to be good value for money. I would think that a key advantage of an SDS Drill is the ability to do a bit of chiselling, so the lack of a Rotation stop on the 650V is a bit surprising and a bit of a let down.
Ryobi 650V On Screwfix
At the current price of £50, this is a reasonable price if the lack of Rotostop is ok for you. At their "was" price of £83, I think it would be too expensive compared to alternatives considering the lack of Chisel ability and accessories.
Ryobi 750V On Screwfix
At the current price of £105 on SFX, there are far more competition to weigh up and I am not qualified to say yea or nah to this being a good deal
At the price I managed to get hold of the 750V - £45 at B&Q, I class that as a great deal.
They started an offer from 5th Aug on this drill at £45 as a get it while it lasts offer - I bought mine yesterday (20th Aug) so there may still be some left at your local B&Q