I can give a bit of my experiences between the 2 brands if you care at all. I have 3 new Petersons, and 2 new Savinellis(hopefully that 3rd arrives soon). As well as 3 Old Petes and 1 Old Sav. The difference between the Old vs New Savinellis is minor, All smoke perfect, nice clean smooth draw, fit and finish is top notch.
I wish I could say the same about the Petes, Older Petes are well done, nice stem fit, clean draw, great fit on the metal work, but the new ones dont smoke worth a f***.
They are drilled tight, they whistle like crazy, draft holes aren't centered, also dont line up with the stems, metal work looks like it was done by a child, the new style rustication looks machine done and kinda like plastic, oh and they all smoke super wet no matter what i change.
I could drone on and on about all the problems I have with the newer Petes, but I still buy them anyway, because I have started to collect the St. Patrick's Day collection, event though I rarely smoke them anymore.
And yes I am fully aware some people will just tell me I'm smoking them wrong, but smoking the same blends as I do in the rest of my pipes, which smoke very consistently, only the NEW Petes give me issue, and maybe one old DeLuxe, but that one has a few repairs in it and a story for another time.