Which sounds more vulger?

[Tdol]

Possibly- it isn't very rude and can be used in a firendly way.

[RonBee]

Well, I’ll Be…
A Rogue Scamp
Britain’s Advertising Standards Authority rejected a complaint about an ad insert in the educational supplement of The Times which referred to children as little ‘buggers’. As in: “Don’t Let the Buggers Get You Down”. It listed teaching guides produced by the London-based publisher Continuum, including: Getting the Buggers to Write; Getting the Buggers to Draw: Getting the Buggers to Think; Getting the Buggers into Languages; and Getting the Buggers to Add Up. The advertisers said the word was inoffensive when applied to a child, when it had the same meaning as ‘rogue scamp.”. -Sky News

Teachers and Experts from US and UK, please comment on! I sometimes heard my ex late boss, an English called his Chinese partner ‘bugger’. Did he really mean ‘chap’ or ‘fellow’?

I don't think "little buggers" would be considered offensive in the US. I can't comment on the British use of the term, but as a verb it has to do with sodomy. Perhaps Red or Tdol will comment.

:)

[Red5]

I'd say that it would be considered rude, yes. However, on a scale of rudeness it would rank pretty low.