I did something similar recently. Not too bad (and I was going from 6.x to 7.x at the same time, changing numbers of ports etc.), though there were a few things that needed fixing up. Export compact will avoid a lot of cruft and just give you what you have changed - much easier to review/edit.
I had a first cut at editing the export file to ready it for the new router, then executed it automatically (rather than step by step) from a clean configuration with
/system/reset-configuration run-after-reset=<export file>
Then look in the log to work out to see where the import has stopped, experiment interactively, and tweak script as necessary, repeat until it runs clean. I did have to reset physically a couple of times when I screwed up, so may not be a good approach if you're remote or if you need to minimise downtime. As suggested up the thread, I ensured that one port wasn't bridged in the config and connected via that.
Enabling the following early in the config script
/tool mac-server mac-winbox
set allowed-interface-list=<something suitable>
Can save a lot of time by enabling you to admin the router even if TCP/IP is not functional, as long as you're on the same (V)LAN.