That's why it's so hard to compare anything. My gear is much more modest, and on my tests, switching back and forth, the Sleek bass sounds best, more pronounced, deeper and cleaner than the SF5s. And of course, it depends on the track, bitrate, etc.
I went back tonight and pulled out my old Creative ZVM with an LOD and the MiniboxE+, and when using that source DAP and the much higher quality amp, the Sleeks really outperform the SF5s to my ears. A much cleaner, vibrant sound - a clear step up from the UEs (at least using those two pieces of gear). I have the PtoS switch "on" on the Minibox. In fact, made me want to revisit the trusty old ZVM, and I may have to rerip and reload some lossless music for its 30GB capacity. In this case, with the amp, it really outshines both the Zune80 and the Sony, neither of which offer line out, of course.
Even so, using the FiiO and the Dowin cable is a step up from just the phones plugged into my DAPs.
Anyway, I do like the UEs as on the go phones, for walking, the gym, etc. They are more comfy than any other phones I own (with the Complys). But I prefer the Sleeks for quiet listening, or when on a plane, etc., for isolation.