Hi Larsalot,
you can’t really go wrong with a Marine Band Deluxe, it’s probably my all round favorite harp.
The Crossover basically has the same reeds as the Deluxe, so it’s not likely to last longer, but the fine tuning is slightly closer to equal temperament. This is useful if you play in different keys on one harp, but may not be relevant for you at the moment. The tone is slightly brighter due to the bamboo comb, which many players prefer.
If you want to play blues and rock, I suggest you buy harps in A and D as your next keys. Many guitar-based songs are in E and A, and those keys are the ones you need to play along in 2nd position (cross harp). I posted an article on this subject here: Harmonica Terminology #2: Cross Harp, Straight Harp and Positions - #14 by SonnyStovepipe
Hope that helps, happy Easter to you too!