i commute 20 miles each way three times a week.
i have a basic bike and put some mavic open sports on it and whizz along nicely. long term average is 16mph for the run so not particulalry fast or slow.
i cannnot justify a new bike as the cheap groupset is cheap to replace worn parts and i do around 4,000 miles a year, and the frame is very comfortable and a good fit even on proper centuries.
i only do maybe four weekend rides a year so all my riding is on this commute.