Ive used subq for years as my trt administration route. The data is out there. I have buddy whos physician has him doing the same route of admin. I cant remember specifics of the research data out there, but i believe it absorbs at a different rate, and has less of a "spike". For me personally, it feels that way as well. As for the welts that some people have experienced. Ive had that experience one time, years ago, but it was when I didnt inject deep enough subq. I think it got caught between the dermal moon and sub-dermal new york city layers. Abscess was nasty for like 2 months. still have the scar.
I shoot cyp esters subq E3D. The amount of mgs is dependent upon the time of year for me. SubQ dosing to me personally *feels* like 85%-90% ish of IM dosing effects, so i increase Subq dosage accordingly. Ive Been on TRT for 5 years give or take and started AAS in the late 90s (my IM injection sites have long ago turned to scar tissue and leather). Again, that 85% ish number could just be mental, Ive never had comparative bloods done, but it feels that way. Having said all that, i personally much prefer subq.