Keep the tub, many people want it and when you sell you'll want as many people as possible to want to buy it.
If you aren't going to sell then do what ever you want and enjoy.
I would try to fix it up and keep a tub.... After 19 years in the business, I can tell you most female Buyers I have worked with want a tub.....Comments are always made when there is none. Male buyers do not necessarily care but many do. Many Buyers will then factor in the price of putting in a tub when they look at your place.
Yes, tubs can be outdated but there are ways to fix them up with refinishing or putting in a newer model. I'd keep one! By the way, you can check out names of tub refinishers on my website under Resources.