Reading has a large hinterland, with lots of small towns and villages around it, so have think about whether you're looking to live in the town itself or on the edge.
The main rail station is in the centre of town - 25 mins to Paddington. However there are other stations feeding into Waterloo, so it depends which part of London you're heading into.
One of the concerns us locals have about the new build estates is that there isn't the local infra structure to support them, eg no shops, schools, GP surgeries etc, so it might be better to concern older properties in established communities with those amenities.
Whether you decide on train station first, school or locality, please bear in mind Reading a a big traffic problem, so if you decide to go for Early, catching the train into Waterloo, don't think St Edwards Prep, over towards Tilehurst is a good fit as a school. At school drop off times, you'd be looking at an hour's round trip. Keep it local for your own sanity if nothing else!
The demand on the local grammars is intense, seriously intense. Do not assume your child will get a place - have a plan b!