I recently had to go through the same decision process that you are now facing. My old bike had a Shimano triple, and the new bike I wanted was available in both a Shimano triple and a SRAM compact double. Interestingly, my use of the chainrings on my old bike was about the same as what you mentioned.

You really have 3 issues here: - Shimano shift method versus SRAM shift method, triple versus compact double, and cassette cog range.

Shimano shift method versus SRAM shift method- This is an issue that you will have to test out for yourself at a bike store. Some folks love SRAM shifting (I'm a recent convert) and some folks don't.

Shimano triple versus SRAM compact double - The SRAM Force group will be lighter than the Shimano Ultegra triple (and also the Shimano Ultegra compact double). The compact double will be faster shifting than the triple.

Cassette cog range - If you choose the SRAM compact double route, I'd suggest you opt for the SRAM 12-32 cassette (12-13-14-15-17-19-22-25-28-32). It would give you the same high gear that you now have and nearly (within a half-step) the same low ratio that you are currently have.