Domscla,
You really need to figure out how much you think you are going to ride and work from there. The components are what drives the bike, and the price. For mid level I would start looking at Shimano 105 components, or Sram Rival. Take your time, do lots of test rides. There are differences in the dimensions of each makers frames, don’t get set on one brand over another, it’s the fit that matters most. The differences in the quality of the frames are really negligible until you make a big price jump. If you need to choose between a carbon frame and 105’s/RIval’s I would stick with the better components and an aluminum frame with carbon forks.
Shop around, test ride everything you think you are going to like, take your time. Live Steve said, you’ll keep this bike longer than most marriages last and if you pick the right one, you’ll be happier than most marriages too.