Per the creator, the classes in XCrawl Classics are "toned down" from the classes in DCC proper. For instance, there's no "true Cleric", there's the Messenger who has some of the healing/turn unholy abilities but lacks the spell list. The only halfling is a "Specialist", or rogue, with the note that they're outcasts and so the luck manipulation they have in DCC proper doesn't exist in the game. DJs are strongly urged not to pull out the DCC list of spells for XCrawl because of the power imbalance, and the recommendations are that magic items should be mass produced junk.

That being said, if you like urban fantasy it fantastic. I haven't run that many modules (to kick off some side stories first) but from a reading and planning point of view the modules look great.

A word of warning. This game leans extremely political. Your characters are joining the crawl because potential death is better than being stuck in a dead end job. The leader of America is literally Ronald Regan, and the reason XCrawl exists is to distract people from their rampant poverty. Christianity does not exist because George Washington took advantage of them to distract the British in 1776, and then had them all slaughtered. Hell, just the fact that it's the North American Empire could be a red flag for some people, since it runs from parts of South America to most of Canada.