Oh my yes, it is good. It is one of my favourite systems, and if I'm not careful I'll gush about it endlessly.

It is geared towards narrative/story heavy play with theatre-of-the-mind action sequences (if the game has action sequences). It's very flexible, and I've run several games in differing genres (Firefly, Superhero, Ponies, and a kitchen-sink post-dual-apocalyptic world with magic and tech and mystery called Broken Lands) and it's always worked great. Especially for a Joe-type game, Cortex smoothly handles different capabilities and abilities and "power levels" across characters very well, so as with Broken Lands mixing hightech with weird Dr Mindbender type things to Lady Jaye covert ops works seamlessly. The different type of scenes and resolution mechanics, plus easy integration of groups/mobs and bosses, also make it easy to use what will highlight the story or action in the moment.
That said, the game as you linked to above is very much a toolkit and can be rather convoluted to get in to, as you need to pick and choose what modules to use for your campaign. Tales of Xadia is the only 'official' RPG currently available using the ruleset, but it has an extensive quickstart available that's a good introduction. You might be able to find older games under Cortex Plus as well (such as Firefly, Smallville, Marvel Superhero Roleplaying, Leverage). There's also a database of fan-produced campaigns (my Broken Lands one included), which can be great to check out and see how they've kitted things together.
https://www.talesofxadia.com/compendium/rules-primer (click on PDF at the top right to download)
The Cortex Prime Hack Database is a list of fan-made rules, settings, and mods for the Cortex Prime roleplaying game designed by Cam Banks et al. and currently published by Dire Wolf Digital. Use the Search box to search and filter by name/title, genre, or creator. Use the Show toggle at the top...
cortexhacks.timbannock.com
If this piques your interest, I would be totally down to work on a Joe Cortex game... it's something that's loosely been bouncing around in my head already.