There is not right amount of processing, at least in a non objective way. It s up to you to decide if the amount is right for your needs or for your taste... Only you can judge if you have achieved what your were trying to do.
If one other doesn t like it shouldn t matter to you that much if the photo serves its purpose...
It s exactly like exposure... there s no right exposure... there s only what you want to show and how well you have achieved it...
IMHO just desaturate the reds and oranges a little, in particular the orange as it's making his dark skin look odd.
Otherwise IMHO they look great. I don't quite have the same aversion to the odd blown highlight the way some people do, I prefer your rendering to the re-worked ones that try to save the bright areas but just look flat.
Honestly, it depends on you. IMO That's part of your vision, post-processing included. If you like the high-contrast or whatever, go for it.
People may criticize "oh it's too *fill in here*" but once you have your own style and signature, people will respect you for that. If they don't, then screw them. They're YOUR photos, not theirs.
I definitely like the second shot better =) I would say that it does look like it went through photoshop, but that's probably just because I know out of camera images can't look that contrasty. But it still looks good and I don't think it's overprocessed, just punchy.
If yours is overprocessed, I wonder what your friend would say about these:
Don't listen to anybody's opinion but your own. Photography, like any artistic endeavor, is completely subjective. If you subject your work to any standard other than your own, you're missing the point & enjoyment level of shooting your own pics.
The dslr and post processing democratization has resulted in a lot of similar effects by otherwise untrained image creators / editors, producing some degree of homogeneity.
That is, essentially, contrast boosting. This maybe cause of your friend's comment of over processing.
When faced with the confusing plethora of adjustment tools, finding a few buttons or sliders that instantly take your image and give it "more" seems to be a common, overused phenomenon.
Tell your "friend" that you shoot photographs; you don't take snapshots.
Oooh, SNAP! I think they both look phenomenal. I'd watch the one on the left though, the oranges, greens, and red are just a touch too vibrant in my opinion - they're distracting a little bit from your model. I do like your process though; it's very bold and lively.