I live in Petersfield now (did live in Porchester) and have a couple of colleges working in Petersfield who commute from IOW – one of them from Ventor. Seems mad to me!
My small concerns would be –
What about a car? Would you want one to get about the island, what about getting about the mainland at the weekends? Would you end up with two or have to suck up big car ferry costs every now and then?
Getting stuff delivered – often online places have a premium for the island similar to Highland Scotland deliveries. I guess a non issue if its small stuff and you have it delivered to work in Pompey.
Job mobility – would you end up staying longer in your job just because of the faff. Living on the mainland you (sounds like your OH is stuck) could get a job 10 miles up or down the coast without issue. But then again you are renting so have flexibility.
Leisure- IOW is great if you dig the 1960s and there is some riding to be had and pace of life is slower. But when it’s Sunday morning and you fancy doing something different to the usual could you really be arsed to leave the island?