Agreed. Playing with other people, especially if they're at a level higher than where you are now, is a fantastic way to learn. Fun too!
However, I'm going to disagree with the "sweating it out with your dollar on the clock" comment, though. First of all, if your lessons are focused on "time is money!" then I'd say either a) your focus is way, WAY off base or b) you're a 14 year old whose parents are paying for your lessons for the sole purpose of turning you into <insert any virtuoso's name here>.
Some of my best lessons, including last night's, are half hours where I hardly play at all, if at all! My instructor and I spend A LOT of time just talking. In fact, simply playing through an exercise perfectly by the next lesson is NEVER a goal. From both my perspective and my instructor's, the primary goal of every lesson is to learn something. And even if I don't play something perfectly, which is often because at age 46 practice time is tough to find, I simply don't care. But I spend a lot of my practice time trying figure out the reason(s) he assigned me whatever he assigned me and if I can come in next week and tell him I figured out that underlying reason he's far happier than if I played it perfectly but completely missed the point. His goal is not to just help me become a better bassist, it's to help me become a better and more well-rounded musician. Good thing, because that's my goal too!
I kind of laugh when I see people give reasons against lessons, especially the ones that are based on "that's just not the way I learn". It's as if they purposely seek out The Headmaster from "The Wall" (hey, I'm a huge Pink Floyd fan and I just saw Roger Waters two nights ago, forgive me

). My lessons are nothing, and I mean
NOTHING, like that. If I didn't have the time to learn to play something perfectly in a given week, who really cares?!?! Life gets in the way sometimes. But I play it as best I can, I show what I learned while working on it (musical concepts, bass techniques, theory concepts, etc.), I come in with questions, and if I have to repeat an exercise this week then, big deal, I repeat it. And when I have a rare week where I can actually find some extra practice time then I make it my goal to wow him next time. In the end, it balances.
But keep in mind that with lessons, *you're* the one paying the bill and if it's not going the way you want, you either work that out with your instructor or you find a new one. But don't let yourself be limited by "that's not how I learn". I mean, we're not talking about high school here!

But if you can find someone who can adapt to your learning style and you're motivated to take yourself to a higher level then I think you just might be pleasantly surprised!
EDIT - Just to clarify, I don't mean to imply that my lessons are easy or they're not serious. My instructor pushes me hard, especially with the things I show interest in or explicitly tell him I want to work on. However, the push is always with encouragement and a "See how far you've come?!" approach rather than with demands, rigidity, and a cookie cutter approach.