I'm with Ian here. It's horses for courses. Ti is understated, whereas carbon tends to be more 'blingy' and in your face. (I generalise of course). If it's a bike for life, I suspect today's carbon bikes will be more prone to going out of fashion simply because of the wide variety of designs and the constant 'innovation' by the manufacturers. Whereas Ti bikes do tend to look the same (due to not usually being painted and following more traditional designs I suspect) and so may stay in fashion for longer. I generalise again. Of course, all that only matters if you care deeply for how it looks! What really matters is the ride, and try before you buy is going to be critical.
I'll declare my hand here, I have an Enigma. And I find the ride quality just brilliant - comfortable, but with a decent turn of speed when you put the power down. So, if I was spending £5k on a bike, I'd be off down to the Enigma factory in a shot to be measured up for a handbuilt, bespoke, British made Ti bike.