If you are going to be living there, do the upgrade for yourself if you want the "better look". If you are getting ready to put the house on the market and are considering this only to boost the resale value, then I'll bet it is a loosing proposition.
However, if it does set your house appart from the others that prospective buyers are looking at, then it might be beneficial to make yours more appealing and move it quicker. You may spend $1500 (guess) replacing the doors, but not get any higher sale price for the house, but if your market is in the doldrums and that is the magic bullet that makes it sell in 1-2 months instead of 10-12 then it may be a worthwile investment.
Only YOU can decide.
Like I said, if you are doing it for yourself to live in the house, then go for it and you will get to appreciate the investment for a few years before you do decide to sell.