Thinking about switching billing software. What software do you currently use for web hosting?

I've been using Client Exec software, but thinking of making a change. For my clients, I only bill yearly due to the lower cost of their hosting plans. It's just not time worthy to bill monthly. Just wanting to look at different software for billing purposes. I don't use the built in software for support tickets, currently most of my customers will either email me or call me directly for what little support they need.

It would be nice to have an app for either Android or IOS to use for billing, but not a need. I'm the oddball user, who uses an Android phone, but has an iPad.