For those considering a move to Mid Sussex (Haywards Heath - Burgess Hill - Hassocks) the following may be useful information.
Transport (commuting to London): The main London-Brighton line passes through Mid Sussex. Haywards Heath is the best location for trains to London - virtually every train stops there, takes around 45 mins to get into London - either Victoria or London Bridge. Burgess Hill, 5 miles further south from H Heath is also served by 2 rail stations (Burgess Hill and Wivelsfield) but not quite as good service as Haywards Heath. Hassocks is about 3 miles further south of Burgess Hill and again has a good train service although not as good as H Heath. Yes seat availability can be a problem but I regularly commute from Wivelsfield and get a a seat at 7.35 as does my husband who goes up earlier at 7.07.
Housing Stock: H Heath is more expensive than both Burgess Hill and Hassocks. For the same price for a 3-bed house in H Heath you can afford a 4-bed in Burgess Hill. Hassocks has a mix of housing too but some areas command a premium being close to the South Downs and having rural outlook.
Schools: There is a good mix of schools in Mid Sussex, both state and private. Private schools in the area include Ardingly College (north of H Heath), Hurstpierpoint College (village near to Hassocks)and Burgess Hill School for Girls. Good state primary schools are found in all areas as too are Secondary schools.
Family Life: Haywards Heath is a large dormitory town with many people working in London. There is a good cafe strip up at the Broadway with shops found further away in South Road and the Orchards (Next, M&S, Robert Dyas etc.). Burgess Hill (where I live now although have lived in H Heath too) is more of a 'family' town. Less posh than H Heath but still a good place to consider. There are plenty of activities going on in both towns for young babies, toddlers etc. I know less about Hassocks apart from it is much smaller with fewer shops but you gain from living in a pleasant countryside area.
Personally you have to consider what is important for you. Is quick commuting a priority (H Heath) or perhaps a larger house (B Hill/Hassocks). Are private schools a priority too?
I have lived in Mid Sussex for most of my life and has been a nice place to grow up and now bring up my young son. Brighton, Gatwick Airport and London are easy to reach and you are not too far from the coast.
Hope this helps for any of you planning a move to Mid Sussex.