I am sort of curious as to how you know so much about these lenses. There are 6 SHG lenses and 8 HG lenses. Shall we assume that you bought them all and used them extensively? Given that you shelled out for 14 rather expensive lenses, shall we assume that you have the experience and expertise to judge lens quality? Since you say that the lenses with nice rendering are in the minority, perhaps you could bless us with a list of those lenses and details on how you came to your conclusions.
I own 3 of the HG lenses and am extremely happy with them. Don't get me wrong, I am not trying to get into a "my equipment is great and yours is not" argument, but the fact is that Michael R. wrote an extremely glowing review of this lens line (http://www.luminous-landscape.com/reviews/lenses/one_upon_a_time.shtml) and I cannot think of a single reason why I would believe your unsupported opinions over the reports of a highly skilled and experienced photographer and my own experiences.
A rather strange and provocative post, especially considering that you started the whole thread asking for advice, and the whole point of my questioning has been to provide
you with the information you were originally requesting!
Its also just as well that you claim you don't want to be getting into a "my equipment is great and yours is not" argument, because your equipment is merely a subset of mine anyway.
Its also strange where you seem to blindly believe Michael's opinions over mine, when he clearly states at the end of the article that he is the owner of only three of the lenses, so Michael himself seems to have failed your criteria stated in "Shall we assume that you bought them all and used them extensively? Given that you shelled out for 14 rather expensive lenses, shall we assume that you have the experience and expertise to judge lens quality?"
But since you're questioning me, FYI I've probably owned around 20-30 Zuiko digital lenses in total since the first E1 was released and I've had the opportunity to use and test even more (from all the various grades) . And I've shot them professionally. And I still own a number of them, including the 50/2 macro and 50-200 that you own (the 12-60 was one I passed over - initially because I already had the 11-22 and 14-54, but subsequently because despite it being a very desirable lens, range and sharpness wise, its probably the most unreliable zuiko out there, with a history of sticking aperture blades, failing SWM drives, and badly fitting lens hood mechanism causing many users to wrench the front element off, plus I don't like the moustache distortion, and since olympus is such a small player, it initially didn't have readily available correction profiles which made workflow a pain).
Also, being a professional photographer, I own and have used many different cameras and lenses from many different manufacturers, so your rather acerbic comment about an assumption that I "have the experience and expertise to judge lens quality" would actually be spot on.
So now you know how I 'know so much about these lenses'.
Your original question was along the lines of asking as to whether the SGH lenses would be a significant step up from the HG. Well, you need to qualify
exactly what you are looking for, but whenever I see people like zippski claiming they are optically in some other league, I ask to see proof, and its never forthcoming. Not because they aren't themselves good, but because the HG lenses tend to be excellent as well. However none of them are in some 'other league' compared to good lenses from other manufacturers either. For example, the 50mm macro is one of the lenses that doesn't suffer from nasty bokeh, but then it has a fair bit of CA wide open. But you read some of the comments from people and you'd think the 50/2 was the best and sharpest lens ever made with no flaws whatsoever. The 50-200, despite its horrible bokeh, is one of my favourite travel lenses ever and I'm willing to bet that it could have taken the stitched landscape zippski posted (as a supposed example of SHG superiority), and nobody would ever be able to tell a difference.
As I said, I'm just trying to cut through the BS. And there is a
lot of BS and hype out there when it comes to Olympus products.
I do sometimes wonder why I bother though. Help and honesty doesn't seem to be something that's appreciated on most forums these days.