Finding a good Push Email provider is slightly harder...
I have my domains with 1&1 (
http://www.1&1.co.uk) so went to them for Push Email too. I did look around, but I wanted a provider in my country (UK) and a reasonable price.
If you already have your own domain name then it's easier to use your existing host, assuming their deals are what you are after.
One point to note:
Sync'ing with an Exchange server can (depending on the provider) require that you accept a Security Policy of their chosing on your devices. 1&1 do have a Policy like this, although they don't mention it anywhere on their site.
If you want to sync you have to accept the Policy (if there is one) at the time you first sync. If you don't accept the Policy it won't let you sync at all - it's that simple.
If you accept the Policy it also gives your service provider the option to force a
Hard Reset on your device - known as a "remote wipe". You don't get an option to "decline" the Reset.
Specifically check that before you sign anything. Reputable hosts shouldn't be a problem, but effectively they can do it at any time so you should be aware of it.