I'm just starting my second 3-year stretch as a governor, having been re-selected for the board (altho' there wasn't much competition, very few people seem to be interested in being governors at our school).
It is very interesting, and certainly gives you a very good insight into the school.
But it is also a very responsible position, and you should remember that.
To do the job properly, you should be prepared to go on the induction course that your LEA should provide, plus other courses over time.. Also bear in mind that you will get lots of paper-work, and need to attend a fair few meetings. There will be one 'full governors' meeting each term, plus one for each committee (we have 2 committees, Finance & Strategic planning, you may sit on one or both). But there may be other meetings if emergencies arise.
The governors may be involved in situations such as parents' complaints against the school (I've mediated in one of these), and pupils exclusions, and head-teacher's appraisals and salary reviews. You need to be prepared to take that on-board.
Governors are also involved in Ofsted inspections (that was fun).
It is VERY rewarding, sometimes the meetings can be fairly frustrating, while also being interesting, and can take over your life if you are not careful.
But having said all that, I would recommend it, providing you think you have the stamina.