Price is hard to say with XYZ at the moment. Your decision depends on if you need the money or not. Currently $75 is not a bad price, but I'm sure you could get a little more now with some waiting/haggling etc.
Who knows what the future will hold. XYZs are gaining momentum, but that really could be domainers pushing the value up trading with each other as investments (false market). Not a lot of XYZs are live sites yet.
So either grab the $75 (or a bit more from negotiations) if you need it, or hold for 6 months or so and monitor the market. If XYZs become more popular, it'll be worth more. Of course if they crash it'll be worth less.