Yeah, there are some really, really pretty bits - Old Isleworth, Riverside, north of London Road going up towards Osterley and bits of the Woodlands estate. These are, obviously, also the expensive bits!
We've been here for 10 years, we're raising our kids here, and we have no plans to leave. There is a lovely community feel, and I would say they yes, it does feel leafy.
It is not utopia - the high street is much less developed than somewhere like Twickenham or Teddington. For bookshops and cinemas, you would need to to into Richmond, but that is so, so easy - one short bus ride, or if you have more time, you can walk there along the river in about 30 minutes. There are bits of actual Richmond that are further away from Richmond town centre than Isleworth! Bushy Park you would need to drive to though.
Syon has a free access bit, and a bit you have to pay to get into. You also have Osterley National Trust and Richmond Park very close by.
Transport links are good. I commute to Oxford Circus, and I can do it in an hour. Trains run into Waterloo, or you can change for the tube at Vauxhall too.
Schools are good, both primary and secondary.
In the spirit of full disclosure, there are two things that put people off Isleworth. One is the flight path to Heathrow. But you will get this everywhere in west/south west London. Just a few hundred metres makes a huge difference, so visit at difference times and on different days - but honestly, we're not in a great location for this, and you get used to it really quickly.
The other is the proximity to the Mogden sewage treatment works. If you live in one of the streets directly surrounding it, then it can smell. I'd never love on the top end of Worton Road, or on Hilary Drive, for exactly that reason. However, pretty much everywhere else, it really isn't a problem. Sometimes, when it rains really, really hard after a dry spell, there is a vague smell of drains for a couple of hours, and that is literally it. People will tell you it is awful but these are not people that currently actually live here. It honestly, really isn't.
Everywhere has drawbacks - and the upside of these two (which genuinely aren't an issue at all), is well priced properties.
Example: https://www.rightmove.co.uk/properties/134851679#/?channel=RES_BUY