I think both are good options. A lot of it depends on what you're going to do with it. I remember those years have an issue with 1-2 shifts being rough and eventually a lot of them having 2nd gear go out. Being that it seems it's had to have a lot of work done already, I would be curious how it was maintained up until that point and how it was ridden. I would definitely test drive both and feel for it. Carb with ethanol fuel these days can cause a lot more maintenance upkeep, and depending on your level of mechanical skill, could cost you more. The FI on the 750 is their 1st gen of it, while it's good, it's not perfect, 2000 they upgraded it a bit. I own a 99 SRAD 750 with 12k miles and it runs like a top even though it had been sitting for a while before I bought it last year and been restoring it. I took it out last night and was so smooth up to 155 before I backed off it. The R6 is about 30 pounds lighter, but the 750 has almost 20 hp more stock. The 750 is pretty nimble for a 750 since it was stuffed into a 600 frame. I don't think you can go wrong with either bike if they were maintained.