My used MD 208 sounded fairly thin out of the box. The Stereophile review points out that this unit requires a long break in period. Perhaps this should be interpreted as it having taken a long time for the reviewer to get used to the sound. (There's a thread here by Marakanetz that challenges the validity of break in for electronics, versus the listener just adapting to the sound over time.) Personally, I thought the change in sound was real over a relatively long break in period for my unit. Nevertheless, the MD 208 still sounds slightly thin driving Thiel 3.6s. Notably, my old Etude in another room seems quite warm, with a socko midbass. On the other hand, I haven't heard the I-5, but I would think it's possible that the same circuit design could sound different in a different chassis. I agree that ultimately separates are better, and I chose a receiver because of installation constraints for this system.