It was a great system that Sony gave up support on way too early in its lifetime (at least in the US). There was only a handful of first party "AAA" type games that were released prior to that, but when it didn't gain major third party support it became the home of some niche genres and indies. The AAA games that did come out like Killzone & Uncharted were excellent and greatly surpassed anything I'd ever seen on mobile platforms prior to them and for quite a while after. The system had an amazing screen (particularly the first generation which was OLED) and optional 3G radio capabilities for gaming on the go.
Sony did their usual BS like requiring these ridiculously expensive proprietary memory cards and a proprietary charging port (at least in the first gen). They also didn't offer an HDMI or DisplayPort out port which was a shame as it could have been like the Switch. Finally, while some games supported cross-saves and/or cross buys (i.e. you get both the Vita & PS4 version in one purchase), that was inconsistent and eventually pretty rare.
For a while, if you liked either indies or the limited genres that flocked to it (JRPGs, Visual Novels, "fan service", etc.) then it was an excellent system. It also received some great games from PS+ over the years including pretty much all its AAAs so many people might have large libraries if they were smart enough to add those games even when they didn't own the system. Overall, it was a great little system that never really received it's fair shake.