I've had these Pannys for a while! Initial impressions as I remember was "woah boomy bass!" Then I took the filters off and the bass subsided a tad bit. After some use and burn in (which I'm pretty sure is more of a mental mind set now...) I began to like these a lot. They had good sound for very very cheap! However, here comes the bad part: I got SICK of these. I can't stand these anymore. They're very nice but something is lacking...all the time. The bass is boomy and not very articulate, rather just thumpy and the isolation is mediocre at best. The highs can be shrill and this is definitely a headphone you can't use to just relax. At first the comfort was very good I liked how they where angled nozzles but now after extended periods of time they hurt my ears. I think it has to do with the shape of the bud being a tiny bit to wide for my ears. Maybe if i changed to some hybrid tips it would help. Also in my right ear the fit is very very weird. I have to jam them in to get a good fit and always after plugging them in i have to give them a light tap to "pop" them for the seal to be correct. Another thing: The microphonics are HORRIBLE. They're still there over the ear but a little subsided. Overall for $6 buck I can't complain especially for grab and go. But if you want a dedicated phone I'd definitely upgrade from these as soon as you can. One plus they have going for them is they are very durable the cable is nice and while they can tangle if just thrown in the pocket they're not tangle machines like iBuds.
Portapros (from memory): The sound signature is sort of similar, fun, engaging and big bass but just lacking...
RE-0's: The complete opposite. Bass is inarticulate and not very well controlled compared to the RE-0's although there is a lot more of it. Microphonics are about the same though . High's and detail's are no where near the RE-0's though. The mids on these little buds are actually pretty descent vocals come clear and loud.
Grado SR-60's: compared to these the buds sounds small the soundstage is almost non existent even against the Grado sound. I did the hole mod to increase the bass on the grado's and it was very much in a separate league to these. Keep in mind these are about $5.
Sennheiser PX 100: The senn's to me where very smooth and dark sounding, something I liked very very much. They where the perfect background or easy listening cans and went very well with techno/electronica. These don't so much but they do go very well with rock and metal. To me the Senn's sounded a bit better with hip hop just because of the open ness and the tight nice bass.
So for $5ish these are thumbs up! As dedicated headphones though these are a no go and even over time these can't hold up to better portables