I've owned Tikka rifles for ~ 10 years - several pre-T-3 models - and I've never had a single problem with any broken bolt shrouds or other parts on them or on current production T-3 models. And they don't get easy treatment. As for the classy thumbhole stock, that is purely a shooter preference.
I've owned one thumbhole - years ago - and the butt stock is laying somewhere on a hill side in the Big Horn Mountains in Wyoming. Fortunately I had a back-up rifle to keep me going.
Beyond that, about all I can say is never buy a Cooper. I've just recently heard that they are all junk and I'm headed out the door now with several gun cases hoping to recover a few dollars and my dignity...

And for me, even though I have long been a Tikka fan, in my eyes they are not heirlooms by any stretch of the imagination... They shoot well for what you pay for them, but you get what you pay for in looks. JMO......
-BCB