I've got a Moots Vamoots RSL, have had Lynskey, Setavento and Litespeed, the Moots is the most "un"Ti ride I have ever had, it is stunning, really stiff, really fast and still comfy, but no more so than a good carbon frame. I thought the Setavento was amazing for the money, Lynskey was good but a bit dull and the Litespeed was like it had a hinge in the middle of it.
I also have a Desalvo Ti crosser, its chalk and cheese to the Moots, much more comfy and forgiving. If it were me and you had £3500 to spend on frame and forks I would get down to Mosquito and test ride 2 bikes, which was what I did, the Vamoots RSL and the IF TiFLW. The IF shaded the Moots, but in the end I bought a very new second hand Vamoots RSL for almost half retail and I never regretted it.
I have owned just about every high end road bike there is, C40, C50, EPS, Look 585, 595, Cannondales of every shape and colour and the Moots Vamoots RSL is hands down by a country mile the best bike I have ever ridden. I put Vittoria Pave tyres on it and ride it all winter, it is honestly a thing of beauty and I find myself still going out to garage just to look it and it makes me catch my breath.
However, I have recently been tempted to add a little something British to the quiver, if I had a spare bit of cash (and surprisingly little considering just how custom he will make them) I would go Columbus XCR or 953 by Donhue Bikes, [url=http://www.donhoubicycles.com/][/url]Thomas is the loveliest bloke, will do whatever your imagination will dream up and they are stunning. If he was in the USA he would be up there with the Vanillas and the Sach's he is a master. For my 50th in a few years, I'll be getting something from him.
But honestly, if you can run to it, go with the Moots, I will never ever sell mine.