It depends on the age group also. BKK is more suitable for the 20-30 something where shopping and partying. BKK is a very stressful place because of the traffic jams and I have never enjoy a single moment driving in BKK. When I first came to Thailand, I did enjoy Bangkok. Ironically, when I first step foot on Pattaya, I really hate this place. The reputation is just not as good as BKK. Many times, very pai seh to tell friends/relatives I am in staying in Pattaya. But now, Pattaya has been my home for the last 5 years. Learnt to adapt. For the over 40s like me, BKK is just to 'exciting' for me.
On the sleazy image of Pattaya. It's much tamer than it appears. Pattaya also not as expensive as BKK, only the taxis are expensive here. The rest are more or less the same price as in Bangkok.