I have a few questions that might help us give you better answers:
1. What concerns are causing you to move away from Gmail?
2. What volume of email are you normally getting in a day? In other words is this an account for business use, personal use, etc?
3. Are there any special features that you may need?
I use iCloud with only the occasional issue. No worse than any other service I've used and more reliable than some.
iCloud should function quite well for that level of use. I have an iCloud account that receives about 50 emails per day (more if you count the spam that gets filtered out) using the built-in Mail program in OS X. Like you I tend to avoid webmail but you can access iCloud that way if you are in a bind.