I'm not an expat (just a South African living in South Africa) but, I've had multiple people from Europe and from other African countries tell me they've had not so good experiences with Afrikaners while living here. I've had at least three white European friends (I'm black) tell me that they've been in a situation where Afrikaners made quite racist remarks (I guess thinking that they share the same sentiments), leaving them completely shocked. A number of black (non-South) African friends have also told me about how a lot of Afrikaners they've interacted with were very unwelcoming. I guess they have these conversations with me because I'm South African and they wanted to know if their experiences were something common (when interacting with Afrikaners).

Not exactly what you're asking for (and I'm not meaning to attack/offend anyone), I'm just sharing because you've asked for foreigners' perceptions on Afrikaners.