Yes, I think he may have gotten a better deal on the open market. However, he's a smallish point guard, who, while he can "score", can't really be counted on to "the scorer" for your team.
I really see Rondo more as a 3rd wheel. You give him a KG and a Pierce, or a Durant and a Joe Johnson, he will make them fly.
He's a guy that makes other people alot better and if he could shoot like Chris Paul, you give him the max in a heart beat.
Right now, if I had cap and Rondo were a free agent, I'd be looking to add LeBron or Wade for max and Rondo shy of max.
Almost every max contract is given to guys who carry the offensive load of your team...
I'm saying he isn't dominant, he absolutely is. But without big time scorers around him to feed? I'm not so sure.
I think he got a good deal now. I also think he probably said "Yeah I might have gotten more this summer, but I like my situation with the Boston Three party and my max day will come.
I think he made a very calculated decision.