Almost anything with a mast will be more high-performance than a Merc (are you a Community Boating sailor? That's where I sailed them decades ago.
I haven't sailed the Hunter 140 but googled it, it's a nice-looking little boat, and weighs well under 500 lbs, and has 100 square feet of sail area. So it'll be much faster, and will rely more on quick and proper crew weight placement, than the heavy old Mercuries. But you'll catch on quick, and you'll be fine, and you'll like it.
Then you'll realize how slow the indestructible Mercs really are. Have fun.