It's very effective....my Test levels have never been more stable. (inject every other day). Of course this is for TRT and not cycles where the amount injected is considerably more at one time. Not sure if it's practical for some going big.
I'm only doing 600mg/wk so that means filling up the 1/2ml syringe 4 times per week. I inject half of the shot into one quad and half into the other (also vary it with alternate delts).
Some would say it is actually IM as I have very little body fat and although the pin is only 1/2" I still feel it entering the muscle. Regardless it's easier, less invasive, and like I said more often, keeps my levels really nice.
Sucks no one had an answer for my sludge question....I think it may be temperature - related.
****FYI I am now doing a small cycle with the Hex, my regular TRT is only 150mg/wk enanthate.