I have r10 and hw100 both in .177 if both were out of the box i would choose 100 everyday, but r10 has been to mr jb and spent £200 on it and now i couldnt choose between them, r10 has more shots per fill + its regulated so power is very Consistent and will shoot 785fps all day long with very little change untill power drops off, the hw100 is pure amazing build quality and very impressive in everyway.
But if buying out of the box hw100 everyday.
When u ask for and Opinion and people give it its all personal Preference, but what the lads have said is great advice, i know that as i use