The frame is the most expensive part of a bicycle you can buy. It’s key to the identity of the bike and says the most about you as a rider. Save yourself some money, don’t buy a bike – buy a frame!
Above all else, a bike that fits you will make you happier on a ride, especially over long distances or up a hill. So, once you’ve found the frame that fits, the next biggest upgrade you should be thinking about is a groupset.