Jomtien Beach is east of Bangkok just past Pattaya. I think Jomtien beach reminds me a bit of places in Florida with many high rise hotels and vacation apartments. It is quite busy but wuieter than Pattaya which is about 10 or 15 minutes North of Jomtien Beach. The beach is quite busy, inparticular at weekend. The Ambassador City Resort in Jomtien has about 5,000 rooms, they say it is the biggest hotel in the world but I am not sure. There are lots of restaurants in Jomtien offering Thai and other food. The Nong Nual Thai seafood restaurant is very popular. You can visit Underwaterworld and Pattaya Park in Jomtien and easily go into Pattaya at night to see the lage Vegas style shows in the huge theaters. You can take trips from Jomtien Beach to Koh Larn island and there are other small islands and beaches to the south.
Jomtien beach has certainly become busier since the new Bangkok Airport opened as now you can travel by a fast expressway from Bangkok Airport all the way to Jomtien Beach in about one and a half hours, which makes it an easy beach to get to from Bangkok if you are on a short visit.