As to the pros and cons of learning at a full and busy ATC field, you certainly get confident flying into large airfields but on the reverse side I always feel a bit nervous landing at an air to ground grass strip.They tend to have a higher percentage of clowns as well who have no qualms about cutting you up/'I've been here for years and this is how we do it here' types. I've been to a few Strips That Shall Remain Nameless where to be frank the standard of flying has been appalling, and I'm just a FNG.
Just in my experience before I'm shot down.
Good luck anyway and let us know how you get on!