UF is undoubtedly a better job but it's probably not as good a fit for Chip. He's a west coast guy and would be the best coach in the PAC 12 the second he signed with UCLA, whereas at UF he'd have to compete with the big boys year in and year out. At UCLA he can win 8-11 games and be there forever.
A better job based on what? If Kelly wants to win, UCLA would be better than the sec gauntlet.
UCLA has no history of winning,
a far worse recruiting base and isn't committed to winning big. It's an above average job but its not elite. On the other hand, UF has a great history, is committed to winning and is situated in an elite recruiting base. The drawbacks are unrealistic expectations, fierce recruiting and the SEC. It's a top 10 job, whereas UCLA might be a top 40 job.