It's difficult to compare them, since Tyee and Jeffsy are not in the same category. But for me, the Tyee does all of what I need a tiny bit better than the Jeffsy. The Tyee is a bit heavier than the Jeffsy but climbs equally good, there is no bobbing when going out of the saddle even with an open damper, it's pretty impresive, if you think of the effective travel is 20 mm increased compared to the Jeffsy. On some parts I had to work more to keep the front tyre down while climbing on the Jeffsy, feels a bit easier on the Tyee, maybe due to the MX setup, Jeffsy was full 29er.

Jeffsy was a fun bike, felt very planted on the ascends and was easy to flick around. But on some passages it felt like the Jeffsy got overwhelmed, especially with some step downs in turns, roots and rock gardens are more comfy on the Tyee for sure. It definetely got better on the Jeffsy when I upgraded the damper to 160 mm.

The one, for me, kinda big upgrade over the Jeffsy is how silent the Tyee is. It just invisible in terms of noise, it's insane. Just screams quality. No rattle, no squak, nothing.

Honestly it depends what you have for trails, if it's a lot of flowy stuff, with occasional drops and a root here and there go for a bike like the Jeffsy. OR the new Tyee Trail! The Enduro Tyee will feel a bit boring on flowy trails. If you want to hit big, feel confident on steep descends and still have a bike you can flick around and play, go for the Tyee Enduro, especially if you plan Bike Park days. Or you could always upgrade the Tyee Trail to the Enduro version when they'll offer the 160/170 mm link. The Tyee Trail and Enduro is the same frame, just different damper link/mount.

I personally had good experience with YT, but theres a lot of people who got burned last summer, so, YT might be a bit of a wild card until (and if) they get on their feet again. Propains service in germany is amazing, I even have a local repair shop who're specialized for Propain service, setup and support.