Using metric system is easy for me as that is what I have always used here in Finland. While I understand that the change is not really easy, it is something that would be beneficial in my view for everyone.
Like some sources say, metric system (or SI) fits more closely to our decimal calculations which is really apparent when you compare how certain things are calculated in scuba diving. The metric formula is usually way more simple.
While information in internet (including wikipedia) can be of dubious value sometimes, the link below is interesting read and shows how US have tried to switch to metric system for quite some time but the public has not really embrased it. Changing something that is second nature for you, is always hard.
I have gone through one such change when our old monetary unit Markka was replaced by Euros. One Euro was around 6 Markkas at time and it became our new currency at 2002. Thats only one change and I still sometimes think how much something cost by converting it to Markka... but that is getting more rare now.
http://en.wikipedia.org/wiki/Metric_..._United_States
/esc