I have a new to me 37.5 and a friend (Vinn) with a 34 and have sailed with him a couple times. There is much more below-decks spaciousness on the 37.5. The 34 is lighter and better in a light breeze, the 37.5 a little more of a solid feel. Both are set up similarly as far as where the sail controls are. I don't think the differences would give a sailor with your experience any trouble. I found the adaptation from a tiller-steered O'Day 30 to the 37.5 surprisingly easy, much easier than from Capri 22 to O'Day 30. But then I had 19 years on the O'Day.