I have a a couple of Ti hardtails now, a Soa and an On One Ti456, I also have a Merlin Works 4 FS. I did come from an S-Works enduro cos I thought I needed it, then I got a rigid SS and suddenly the S-Works felt dull, flatenned everything, awsome but needed no skill.
My Ti 456 is the one I generally reach for and with 150mm DT Swiss up front and a Rohloff it is pretty bullet proof, although coming in at 26lbs. it is has pretty much the same angles as a 140 forked version as the DT is very short axle to crown, It is VERY different from the Soda, much stiffer and direct in the corners but still compliant like a good steel HT (my SS)
The Soda was more flexy, more lively, you whipped it about which was huge fun through the singletrack but a bit too pingy on rocks for me.
MY FS is also Ti but I wanted a FS that was closed to a HT but comfy for all day riding when I was knackered and wanted to pedal through stuff and for racing enduro's which is what it has turned out to b, the key for me with the FS was the longevity and ease of keping a Ti frame looking good.
I gotta say I love Ti bikes but I also love steel bikes, I would say a good Ti bike has the same feel as a good steel one, a little more lively perhaps, but definitely lighter and longer lasting and easier to keep looking good, the Ti456 is I would say stiffer than the steel one and more than 2lbs lighter in the frame....I do like skinny tubes though.
Interestingly the livelyness still comes through on the Merlin FS, even thou it is theoretically isolated.
I also find that a Ti HT bought s/H retains its value very well so would be a relatively cheap trial, initial investment excepted.