Westcliff on see is really nothing special. Its just like any other town without a good high street and without anything worth mentioning to do so if you are reading this because you are thinking of visiting southend for a holiday then westcliff is definately worth missing out on!!!
'On-sea' makes it sound like a quaint little seaside village...the closest you get to that here is just a view of the sea and southend-on-sea (which IS worth visiting!!!).
There are some grotty housing estates, some larger prettier houses, a range of architecture, parks (some very small with a swing if your lucky and some even smaller!), and a few schools (one of which is westcliff high for boys/girls - a grammer school).
Its close to southend and leigh - both pretty to visit in the summer. It can be reached by c2c line which takes you to near the sea front...more southend sea front than westcliff in my opinion but thats probably because the driver knows you'd rather be there anyway ;)