Poole is part of BCP council area (Bournemouth,Poole, Christchurch).
Poole is poverty struck in lots of places, large very poor estates, town centre is quite run down, nothing but charity shops down the high street & bus station scary full of teens who would stab you if you look at them the wrong way no joke.
Yes certain parts of Poole (Sandbanks, Branksome Park, Candford Cliffs, Lilliput, Lower Parkstone) are lovely but only if you have lots of money.
Bournemouth is more diverse, also there are lots of students, but also huge drug problems & large homeless population. Town centre fast becoming run down sadly with lots of boarded up shops & bedding although still plenty to do for younger people.
You have to be careful at night in certain places like the Gardens & pier area.
There are various areas in Bournemouth such as Charminster, Boscombe, Pokesdown, Southbourne, Westbourne, etc that have character of their own. Ok, Boscombe is a bit notorious for druggies but does have some good points too.
Christchurch is an attractive town with a strange mixture of wealth & deprivation yet again, also with Highcliffe just down the road having the highest number of elderly residents in the country which, together with Bournemouth's second highest number of drug addicts in the country (I could be wrong now) puts a lot of pressure on the amalgamated UHD hospitals.
The major traffic congestion in the area is also a big issue really if you drive.
But... personally I like the Bournemouth area as it never gets boring, there's always somewhere to have a coffee, somewhere to walk to, lots of bars. restaurants, cinemas to go at night, new people to meet.
Also because nearby are some of the best beaches, forests, & countryside in the UK to enjoy.