To me a HW77 is a .177 machine. In that calibre it excels.
To me a .22 is for shooting and fun, which translates to a break barrel.

I've had a HW35E in .177 and it did little for me. I'd have one in .22.
I have a Venom HW77 in .177, can't say I'll ever let it go. In fact all the HW77's in .177 that have crossed my path have tac drived.

I can't see any good reason to get either new as both can be found second hand and many older ones have nicer furniture that the present factory offerings. Anything more modern in the HW range then OK, but even then loads sold and there are plenty hardly used ones on the market. Frankly springers are hard to master for many in this modern age, and why bother when a PCP delivers... so they "upgrade" quite quickly leaving well priced new model springers for those who appreciate the springer quirks.