@Dca ****
I've crossed into and out of Thailand through nearly every land border checkpoint the country shares with it's neighbors.
The only ones I haven't tried are the borders between Narathiwat/Yala and Malaysia, as they're located in dodgy areas, with the security situation on the Thai side quite worrying.
I also haven't tried the Phayao and Beung Kan crossings with Laos (though I've been to both, just haven't actually crossed over). I am sure I'll be crossing those in the relatively near future, especially once the new bridge in Beung Kan opens next year.