We signed up for ChannelReply a few weeks ago after ReplyManager made the new horrific changes to their service (don't even get me started). Honestly, its the best thing that happened to us.
Zendesk is incredible - blows away the competition and the ChannelReply integration is the icing on the cake. We can handle way more messages now, organization is much better and the automated responses and Macros built in are perfect for us. We get all order info pulled into every ticket and the ChannelReply team is frickin amazing.
Handled all my questions and basically set my account up for me in like 15 minutes. Never lookin back!