[bmuursh]

Personally I'd probably go for job #1 with the more interesting and challenging work. If the work truly is challenging then you should be able to build a strong skill set that will enable you to move onto #2-esque opportunities in the future. You should also take other things into consideration, do you get better benefits (you're in the states so health care should of importance to you), time off, et al...

Which team do you prefer, remember you will spend a lot of time with them, make sure you get along. You mentioned a "strong engineer"; from what you've said I guess you plan to learn from him. If that is the case then make sure you get along well with him in particular. Can you contact people who have worked with them before? Find out what they're truly like...