Super-Flite is a fast, fun game but I like to route it where beginners play. The ruleset is simple, but experienced players might find it too simple and lose interest in it.
Space Mission has some advantages over Super-Flite. It is a four player, which I prefer over a two player, but may not matter to you. I consider it one of the few iconic Williams pins from the 70s. It has more and varied targets to shoot for, i.e. a spinner and the horseshoe loop at the top of the playfield. Super-Flite’s art package is awesome with that B-58 Hustler look-alike, but Space Mission has that beautiful, stunningly blue art package. I’ve never been a fan of swinging targets though, especially with the slotted kick-backs - too many instant drains. But how I feel isn’t important. If you like the swinging targets and the kick-backs, or are ambivalent to them, then Space Mission would be my recommendation. So far a Space Mission has eluded me, but I would like to have one in my collection one day.
Play 50-100 games on each and then decide which one brings you the most joy. ‘Trusting your gut’ is good advice.