I've been riding an Ace for around 6 years now and pushing 30,000m, and it is a more than capable machine. When it came out there was little that could touch it in the sportbike world. With quotes such as "The YZF1000R, like few other Open bikes before it, is a supremely balanced package offering all-around abilities that don't come at the expense of cutting-edge performance. Yamaha's Open-classer will commute, it will tour, and above all, it will rail". But it was a bike that was only available in the states for one year till the R1 came out. But over sea's it was available till I think 07'.
No, it is not as svelte as a newer machine R1/R6 it is what I would say is the last of the "big sportbikes" with a longer wheelbase and weighing 50lbs more than an R1, 6lbs more than the R6, and 23lbs more than the Cat "DRY", but it is more than capable to run with them. The Ace is down 12 hp to an 02 R1, but has 5ft/lb more torque. A 99 R6 is down 20 hp and 31ft/lb and a Cat is 40 hp and 31ft/lb down. You need to remember that the racing series all had a 750cc limit. So the open classed bikes were not a racer replica like the new ones.
Sorry for the history lesson but if you can't tell I am very fond of my Ace. Milage is great getting 45 to 50 mpg, 500 mile days are not hard on my fat old body. That being said the Ace fits my body style and it may not for you. It all depends on what type of riding and what you want. Any of them would be a great buy.
And cad600 who says if you can get past the styling
They be a damn sexy machine