Last year I started running occasional four-session long RPG adventures using different systems and genres each time; I had a lot of luck and really enjoyed a Western game with Go Fer' Yer Gun, a post-apocalyptic game with Gamma World, and a pulp jungle game with Savage Worlds. Alas, not every swing can be a home run, and I'm sorry to say that my experience running a super hero game with Silver Age Sentinels was a strike out. I have to give credit where it's due for the production quality and design of the core rulebook: it's a handsome, attractive book without a single typo (that I noticed) and a wealth of information about the setting and its heroes and villains. The system itself though, at least the Tri-Stat version we used, just didn't seem balanced at all. Even with a "standard" 150 point super hero build, a first-time player was able to make a hero that could drop any villain with a single attack, and the cost of powers were so cheap that it was easy to have big-deal super powers like super speed, regeneration, resurrection, and more on a single character. The system was also rather clunky and rules-heavy, and didn't have the sort of special features to really make a session feel like a comic book.
Even worse, the published adventure I ran, Emergency Response, was frankly kind of bland and, for a reason I do not understand, gave the main villain a trivial number of "health points." The group I ran the adventure for dropped him with two quick hits when they first encountered him in the third session, and I just couldn't figure out a plausible way to continue the adventure afterward (though, admittedly, I wasn't at my best that night and should have at least come up with an epilogue of some sort for the Reserve, consisting of Red Scorpion, Techno, Ms. Mystic, and Nitro).
I think maybe I could get something good going with Silver Age Sentinels if I created my own adventure, instituted a few house rules (such as Numenera's feature of offering the players XP to allow a forced plot development), and capped the number of points that could be spent on super powers. But that'd be a lot of work, and with many other super hero games on the market I'd probably be more tempted to try another one than revisit this one.
But, ever onward. Next stop: Victorian exploration of the solar system in Space 1889!