Shaddow,
I tried Sumo's to open up with, but I couldn't bring myself to continue with them. I did feel greater alleviation in my lumbar from performing Sumo's, as compared to Romanian, but my muscle coordination, angles of strength, mechanical torque, neuro-muscular familiarity & efficiency and muscle strength development is so well tuned to Romanians, that performing Sumo's felt like trying to throw a ball with my non-dominant hand. It was do-able, but it felt awkward and undesirably challenging.
I think if I had no other option what-so-ever, I would do Sumo's, but I decided to just go Romanian and take it uber light. I'm all for variation in all types of forms & angles to maximally stimulate muscle growth, but Deads are more performance based for me, so switching to that unfamiliar stance was not a pleasant experience. I tried the 225 Sumo style, and 225 is literally a warm up weight for me in Romanian style, but performing it Sumo felt like I probably could have pulled 5 reps if I tried really hard.
Again, admittedly, when I comes to Dead lifts, I do have somewhat of an ego, but not so much for everyone else to see, but for myself. There's a certain level of proficiency that I can't seem to let myself fall beneath, so even if Romanian's have to be performed extremely light for now, it feels like home.
Was that mellow-dramatic enough?