Wow. There's an awful lot of small-timers here...

I say go with the larger company, for now.

Couple of reasons why:

1) Small mechanical companies have virtually NO money for R&D. They typically find a niche, and they stay there.

2) The bigger company is a resume builder, nothing more, unless you find something there you really like. You'll make more pay in short term, which may allow you to take a lesser paying job later on in life, to do what you "really want" to do.

3) You say you've already "maxed" out where you currently work; another mom & pop shop is going to have the same effect for you. It'll be fun for a while, then you're going to feel like you've got nothing more you can learn from them.

4) Get to a larger firm that can afford real 3D modeling software, like Solidworks. Autodesk Inventor is a fairly archaic program that can only compete with the better 3D programs out there because it's cheaper. Hence the reason the place you're at right now, and the small place you have the offer from, use it. Go with a larger firm, so you can learn new software on bigger jobs. It'll help you be able to handle the smaller ones later on.

5) Never, ever, ever underestimate the benefits of a great health plan. I'm 28, and two years ago I got kidney stones completely out of the blue. Shiite happens. Make sure you've got great health insurance before it does... If I hadn't been with my company with great benefits, I can't imagine how much that would have cost. All I know is everytime I went to the doctor's office, they ordered 2 CT scans at $3k apeice, but with my insurance plan, I paid $0 out of pocket for 'em.

6) Don't look at the larger firm as the place you're going to stay forever for retirement. It ain't gonna' happen... Virtually noone stays at the same company anymore, ESPECIALLY engineers. We get bored too easily. But build the resume, now, so when you do get bored, you'll be able to put your name out there for pretty much anything.

Sorry, guys. I just don't believe in the small business for a new graduate anymore. I worked at several; the problem with small businesses is they usually think small. And if you have aspirations for ANYTHING other than what mom or pop have in mind, you spend all your time frustrated.

I currently work at a firm that has almost 4,000 employees, of which over 3,000 are engineers, architects, and planners. (Civil Engineering) I wouldn't go back to the little firms I've worked for in the past if you paid me a million a year. It just wasn't worth the frustration of working with small-minded people.