Trigger jobs can be done yourself if you're the DIY type, complete instructions can be found in the FAQs and Help sticky. H&R at Gardner used to do free trigger jobs, but since the move to Ilion, Remington may no longer be doing them, that remains to be seen. Any competent gunsmith can do them too.
The standard wood and Ultra stocks have a bolt hole drilled thru them to access the stock bolt, it makes a great place to add weight or a mercury recoil reducer, the synthetic stock are hollow so they can be weighted too. The SS Ultra 45-70 thumbhole has no hole, but most folks find they help reduce felt recoil just by their design. The bigger issue with the 45-70 Ultra is the thin recoil pad that comes on it, I swapped mine out for a camo t-hole stock with a Decelarator pad, that can be done with any stock, Limbsaver makes some fantastic pads that will bolt on a lot of H&R stocks, both syn and wood/lam, see the FAQs for info on that.
The value of the SS Ultra 45-70 is just a matter of personal preference, I bought one just cuz I wanted it, it's the first all stainless H&R ever made, I'll be shooting handloaded 300gr Barnes TSX-FBs thru it using Barnes' data this Wednesday, watch for my range report.
Tim