Took me a about a day to get used to it in Ireland, then it wasn't too hard. First day was the worst since we flew overnight. The hardest part, right to the end, was parking lots as I just couldn't get my head wrapped around where to be.
I really liked having a manual, not only a little less expensive but also kept me really engaged while driving. Plus it's fun.
Most of what we want to do on this trip will be easier with a car. I'm sure we could make this trip work with trains & busses but the time & PIA factor makes getting car worth it.
EDIT - I still can't believe some of the roads in Ireland are two way traffic.......and the Irish drive like they never expect to meet oncoming traffic.