I had accounts with kasikorn, scb and bangkok bank.

Scb and kasikorn kind of similar.

Kasikorns web interface is bot netter than scb. They both have decent apps.

I think scb is a bit better just because in 10 years across 3 or so branches I have never had an issue. 

Kasikorn was ok but they did trick me into buying 2x insurances though.

Bangkok Bank however I would steer clear of. Everything I tried to do with them ever was a pain in the butt. They still try to give you useless union pay cards. In the end I had to close it down as they simply refused to give me a regular debit MasterCard. 

That said experiences change from branch to branch and "there's no problem until there's a problem" wherever you go.

 

Krungsri bank has always been the best for me, But if you ever need to use an agent for visa/ extensions then the BKK bank will be needed. 

I don’t think there is much difference between the banks.  In general I find that banks here are  behind the times compared to the west.  
For example I have Bangkok Bank. They still use passbooks here.  With my bank in the states I can change and update passwords online.  I can also sign up for other services.  Here I have to go to the bank and sign ten different forms.  

I have been banking with Krungsri for nearly 17 years and this month transferred 60,000 baht in to my current account.  They charged me over 1,000 baht to accept my money, which they will make interest on - disgraceful.  I am currently looking at other banks for a better deal, where I don't get charged for giving them money!

Bangkok Bank is the most widely recognised and farang friendly. Only bank that regularly identifies FTTs as FTTs and deals direct with Wise. Would have preferred SCB as my wife had 2 mortgages with them which I paid and eventually paid off but they refused me. BB were initially difficult but as my wife had an account with them and they saw my pension details they accepted me.