I liked the Glacier. Mine had a lot of hiss and after I turned it down to the point that it was gone I could max our the volume on a lot of music that still left me wanting for more. I told Todd about this and he said he would test it. This is through my Hd25-1 II.
Through my Note 2 via OTG and to the glacier it was great but not significantly better than the Headstreamer Mobile I had. It was a bit faster but I think that ws due to the fact that the Glacier is significantly louder. Through my Ipod video 5.5 via LOD it was OK not great. I was using a Fiio LOD but still not as impressive. I know that the LOD is not as good as going to DAC/Amp but.....
I've never had any problems with hiss, but I do get a lot of RF interference. I think the Apex Glacier is a good amp but the DAC is a bit lacking. I like using my Stoner Acoustics UD100 with the Apex as it retains the Apex's warmth but improves the clarity & punch.
I just ordered a Meier Quickstep so if that's a lot better I may sell the Apex Glacier, although I do like it's warm sound.