I like that there're a lot of shells people can use, but I'm sticking with bash.

I quite like the autocompletion thing I guess, but I find it a little distracting to see the previous options for a command I used. If I want to recall a previous command, I'll usually just do ctrl-r and start typing. If I don't want to use the same arguments I used before, I don't want to see stuff come up under my cursor.

I could get by with the environment differences - though instead of doing ENV foo=bar command I'd probably do foo=bar; export foo; command which is almost the same thing and should work everywhere. If I'm going to have to adjust my syntax to get it to work in bash (which everyone and their dog has) I might as well make it work in as many shells as possible.

The lack of && is more of a problem. Don't like that at all!

I never liked oh-my-zsh, either.