Need advice on taking a bus from Siem Reap to Bangkok.

Can anyone advice me on the best bus service from Siem Reap to Bankok? Is there even a bus that goes directly there, or do you have to change at the border? If so which is the best bus to get from the Cambodia/Thai border into Bangkok. I need to go to Bumrungrad Hospital for knee a problem. I have read some horror stories on the net, but not sure of any improvements since then, and with a bad knee I sure don't want to get myself in a fix.

Thank you!

GP

yes all rides change at the border. and you will go through customs as well. overnight bus but dont leave and valuables in baggage under .keep on you at all times.

i dont know if it is common but i took bus to bangkok and spent 5hrs in line at the border crossing with tons of people in the hot sun it was awful !

It is common to have to wait hours at border crossings.
This adds loads of time to the trip.
Flying may be more pricey but is way less time consuming and more comfortable.

if you want to bribe you need to speak to someone who can converse
i paid 10usd above visa price and it took 30mins from thai to cambo not the reverse unless you have thai speaking person with you who can do the same going opposite direction.

i did notice at the thai border that the tour buses and passengers dont wait in line they go right to the front and are through in minutes !same on tour buses into vietnam ho waiting  !i would never go on the bus agian on the other side of thai border we were crammed into vans for the ride to bangkok all in all it was a not that pleasent of a day lol!but what the hell it was a great  asian holiday i will be bac soon !asians rock !