I believe a bicycle should disappear underneath you, that your commute should be the highlight of your day, that you should want to make multiple trips to the store just for the ride. It is impossible for this to happen when your not comfy. In order for this to happen your bicycle needs to fit like a glove.
The bike you spend the most time on should fit you the best and the bike that fits you the best will be the bike you spend the most time on.
