playing both, I really think the HD500 is great for everything in the higher gain realm.. If I only played metal, I probably would of stuck with my HD500, but since cleans are #1 priority for me, I sold my HD500 and trying to sell some other things to pick up a Standard, hoping the cleans are abit better than the HD500, but honestly I still have some doubts it will be, the HD500 was really good.
I originally was going to buy a real tube amp again, a top of the line one.. but I went to the store to try all the best amps they had around here (Fenders, Mesa Lonestar / recto/etc, H&Ks, many more) and honestly the HD500 came out on top of everything except the Mesa Mark V for higain, and the Lonestar for cleans. Unfortunately, neither of those amps could do both cleans and distortions good enough for me, so I am sticking with the modeller game, and going to try the Standard.
My point being; While the HD500 may not be the axe-fx, its pretty damn close, to the point where Im very hesitant to spend 5 times the price on one.. If I wasnt able to sell the HD500 and my Randall RM4 to cover the costs of a Standard without adding money, I would of stuck with the HD500. Its just that little extra clean tone I needed.. and the fact I want a rack unit, not a floorboard.
By the way, if you do get the HD500 for now until your II comes, you can always use the HD500 as a MIDI controller once the II gets here. Its a very solid MIDI controller, easy to program and a great backup incase the II malfunctioned on stage; you would have another amp/effects unit thats 95% as good.