The border at O'smach is definetly open for foreigners. Exited Cambodia there with one Thai registered bike and one Cambodian registration. Thai 30 day visas on entry and normal customs , but quick as no one goes thru with vehicles as they park on the Thai side a walk/songtow to the casinos just across the border.On the Thai side it is called Chong Chom? The border post can be found by following Higway 214 south from Surin. From the Cambodian side the road from Anlong Veng to O'smach is very good, 100-120 kmh easy, demining going on along the road.The road up the escarpment is also good.Also a good road north from the Sisophon-Siem Riep road.An alternate border post for those sick of Aranyapratet. Also noticed new tempory export procedures at Aran, now need to stamp passport out first, then back to customs, then to immigaration again for an airline crew(yes!) list , 2 copies of everything (B50 for copies-no receipt), then exit at immigration. Takes a lot longer than the previous 5 minutes. Cambodian side, if you stop at the customs they want to see a Carnet, which of course you can't get for a Thai rego bike.After a while they just stamp the back of the Thai export paper if you agree to come back thru there on the way back, I never have because you normally can't find anyone or I'm in a hurry. Interesting to note that there was no Cambodian customs at O'smach.