Titanium's reputation for extremely long life frames was built up with straight gauge tubes but in more recent times milled tubes and other techniques have enabled lighter titanium frames but the lifespan has been reduced so to be honest I'd want straight gauge tubes, titanium frames can be horrifically expensive to repair to the point you may as well just replace. Titanium is a thing of beauty and its relatively easy to always make titanium look brand new, it feels nice to the touch too. I don't have one myself but they definitely have a high drool rating.
Seems like a cracking price. Huge convert to titanium for comfort and 105 is spot on. Wish I could justify it. I think if you are a reviewer comparing lots of bikes then sure you will notice nuanced stuff like ride stiffness, bit like wine tasting. For majority of riders I be looking at comfort and think this will feel like a really competent bike and ti will make it feel a bit special.
Secondhand market is crazy at the moment, Covid tax has made sure of that. I'm after a cheap Ali bike for my turbo but anything reasonable (and not stolen) is £400-£500. I currently have a Spesh Allez on my turbo, picked it up for £115 a few years ago, same thing at the moment is £300+ on fleabay. Not really comparing apple with apples, you are talking about an old, turbo bike (mine is hanging), probably 9/10 speed cassette with a new 11 speed Ti. Your previous owner might have looked after their bike on the turbo but the flexing on the BB and constant shower of sweat ruins bikes and dissolves bars. My front mech is pretty much seized and I regularly strip mine – that's what 4-5 hard sessions a week does for you. Glad you got a good deal but they seem thin on the ground at the moment. Not a time to be buying bikes that's for sure!
Lovely bike. You won't find that second hand.
The picture is a stock image of the original specification from Sabbath in ~2014 - Spa Cycles will build up to the spec on their website