So if you are ever deciding to come to Thailand for a vacation, by default Krabi will be on your radar. I know that Phuket and Pattaya are far more popular destinations and Phuket in my mind is better than any beaches that exist elsewhere in Thailand. So if you can handle the crowds I say, go there.
Pattaya sucks. The only reason to go to Pattaya is because you are interested in sex-tourism and if you are, I'm not judging - go for it. If that is what floats your boat well, there is likely no place better than Pattaya for go-go bars anywhere in the world. However, if for whatever reason you end up with your sites set on Krabi you should consider Krabi-town instead of the beach areas.
If you are choosing to stay in Krabi, the places you are booking will likely show you pictures like the one above to pique your interest. While that photo is technically in Krabi (province) it is on a national park island and you can't stay there the same as everyone else. You CAN pay money to go there during the day and this is possible from the beach areas as well as the main town. If you are a frugal traveler, your money will go much further if you stay in the town.
Most people who visit here decide to stay at the beach. They have these dreams of beachfront bungalows where they wake up in the morning, awakened by the sounds of the sea to casually stroll down to their private slice of paradise. ahhhh yeah.
Snap out of it! These places for the most part do not exist and I am pretty certain that on the Krabi mainland (the places you are likely to encounter as a Krabi visitor) they don't exist at all. You will be staying in a high-rise that is 700 meters from the beach and even though it is nice you will not have your own private beach. Therefore, hear me out about staying in Krabitown.
Krabitown is about 17km from the beach areas but has the same access to the same things that you will have access to if you stay at the beach. It also has the wonderful aspect of costing about 25% as much to stay in it. There are ultra cheap guesthouses as low as 200B a night and also full service resorts that cost 3000+ per night. I would shoot for mid range. For say, $20 a night you can get an air-con double with balcony easily. You will NOT be able to accomplish this at the beach.
In Krabitown they have genuine Thai stuff like markets and a real city where the restaruant's popularity is based on the quality of their food rather than how close they are to the beach.
this restaurant is a relatively famous one on the riverside where you can eat what might be the most amazing seafood you have had in your life for $10 a person
You also will have much easier and cheaper access to jungle stuff, the temples, as well as reduced prices on taxis to wherever you want to go. If you stay at the beach, you pay tourist beach prices. If you stay in town, you pay well.... half that much. The food is much better and there is also a magnificent riverside park complete with food for as low as 50 cents.
Basically, if you find yourself traveling to Krabi in the future and you are at all price sensitive, skip the beach and stay in the town. You will see the same stuff and spend half the amount of money.