I'm considering getting a replacement but not sure if I should get the Magic Mouse 2.
Personally, after 30 seconds of using the Mighty/Magic mouse, I want to scream and throw it across the room - its horrible to hold, doesn't support your palm and using the gestures is like trying to do a Vulcan salute. Via colleagues I've found the Magic Mouse 1 (with the AA batteries) to be unreliable - problems with the battery terminals - and (as others have said) the charging arrangement on the Magic Mouse 2 is hysterically stupid.
Question is, though, do
you like using the Magic Mouse - because the
important thing about a mouse is that you, personally, are comfortable using it as a mouse - and that's highly subjective. If so, I think I'd reluctantly go for the rechargeable MM2 over the MM1 (and try and remember to plug it in when I took a break).
Best thing, if you get a chance, is to find a store with a range of mice on display and pick the one you like the feel of most.
The Magic Trackpad 2, however, is great for general use (my tip - go into 'accessibility' and enable 3-finger drag - its transformative) although I find a couple of things (some games, graphics work) still work best with a mouse. Maybe try one of those, and stick with your Magic Mouse 1?
I use a mixture of Magic Trackpad 2 and a Logitech MX Master mouse.