You are smart to collect info. The good news is that you can be successful any direction you choose - so it's just a matter of deciding what's best.
Independence is great...BUT - it takes time and effort to manage the PTO as a 501(c)(3). The PTO is truly a non-profit business. It's not an overwhelming amount of work, but you do need to be prepared to take it on. You'll have to follow the IRS rules, file an informational return, keep your paperwork up to date, etc.
As far as independence from the school - in my opinion, no parent group is truly exempt. You will always be tied to the school and its policies, so it's never going to be a free ticket.
Regarding grants - I'd be skeptical also. Yes, you probably do need to be a 501(c)(3) before most entities would award grants. However, applying for grants and maintaining the required documentation is a significant amount of effort. If you are going after anything big, it's going to take the coordination and approval of the school. Generally, the school district is better equipped to apply for these than a PTO.
On the positive side, if you are having problems with the district exercising too much control or if you have volunteers who are wiling to invest the time in working on grants and this is really an area you want to pursue, then you may want to proceed.
Hi, I am looking for some input. We are currently a PTO under the "umbrella" of our school. Meaning we are not a seperate registered organization, also meaning that the school board has some input on how we manage things. They do not aggressively use this input. Some members of our PTO board think we should become a seperate independant entity of our school,(501C3), which would mean we would not have to answer to the school in any way. We would have our own tax exempt ID, our own insurance, etc. They have also said that by doing this we would be eligible for more funds/grants that for some reason they say the school could not get by themselves. This is what made/makes me skeptical. I want what is best for our school/children and do not have any facts on this type of situation. Does anyone out there have any insight?