There will *always* be something new to learn but I think you've probably got the right skill-set for the position. The real question is whether or not you are happy with your current position, and if moving to another company would be to your advantage. Unless you consider your current gig to be the ideal setup for you for the foreseeable future, I'd suggest at least going in for the interview.
Worst case: you and the company are not a good fit for one another, you don't get an offer, and you end up staying with your current company. In other words, no change.
Best case: they make you an amazing offer, with higher pay, better assignments, etc, and your career gets a major boost. I'd say go for it