I traded with a friend my Intellivision with a couple dozen games for his Vectrex with 4 or 5 titles. After the honeymoon period, I regretted it pretty bad.
The system itself was actually pretty interesting for the time and the vector graphics (think arcade Asteroids) were rad as hell. But the library was shallow as hell and the titles themselves didn't have near the depth of Intellivision releases.
Vectrex games had some cool arcade ports but it felt like that was as far as it went for depth of experience. They were all designed for quick-shot sessions which I quickly grew tired of. Compared to meatier Intellivion software like AD&D Treasure of Tarmin (an actual gd 3D dungeon crawler!), MLB/NFL/PGA sports, legit strat/sim games like Sub Hunt and Utopia. Well, Vectrex offerings felt paper-thin by comparison.
The funny thing is that the Vectrex console is a cool oddity in modern times. And I think it goes for a pretty penny on Ebay. But man, back in the early 80's that damn trade had me full of regrets, lol.