Pros: Good highs like the RS1, the Grado PRaT, price
Cons: Midrange a little thin sounding, can be a bit bright compared to RS1
Note: Impressions based on using new bowl pads as worn in bowl pads can change the sound significantly.
RS2i reminds me of the SR125 I once had, bright and not as full bodied sounding as the RS1. My first impression was that it sounded quite detailed then I realized it is because the bass presence is not as strong as the RS1 so I was a little fooled at the beginning. It is not any less aggressive than what you'd expect from a grado headphone.
I will be comparing against a buttonless RS1 (not RS1i or RS1e) for this quick review using bowl pads.
Highs: Pretty much right up there with the RS1, well extended and detailed. It doesn't sound less refined. I could not tell if there's any difference in this category. This aspect is the closest to the RS1, the mids and lows is where things start to separate the RS1 from the RS2i.
Mids: The presentation is a little different. The midrange sound thinner on the RS2i so it seems a tad recessed to the RS1. It sounds a little more "hollow" compared to the RS1; imagine a somewhat V shape where the mid and bass is a 0dB and the mid is minus a few dB. This is most noticeable when comparing vocals as I find myself needing to turn the volume up so the vocals sound as loud as on the RS1 but the highs become too much. Guitars still sound great though, but again thinner on the RS2e compared to RS1. Cymbals sound more distant and slightly less refined as I heard some graininess. Since the mids are more recessed the highs are more evident, making it sound brighter than the RS1.
Lows: RS1 slams harder here and the mid bass is more present as well. It is easy to hear the difference for the kick drum; it's more quiet on the RS2i. Bass guitar is very easy to follow on the RS1 compared to the RS2i. This could be the difference in cup height difference as the RS1 has deeper cups. This makes the RS1 have more body than the RS2i which sounds lighter in comparison. To me this category combined with the midrange difference is what is most obvious. The RS1 simply has a fuller sound than the RS2i and the RS2i does not excel in any aspect in regards to bass vs the RS1.
Summary vs RS1:
Highs = Equal
Mids = RS1
Lows = RS1
Bright = RS2i
Soundstage = RS1
Detail = Equal
Comfort = Equal
Build quality = RS1
I think someone who hasn't heard the RS1 compared to the RS2i will be very happy with it compared to the prestige series plastic headphones. I just wished the midrange was fuller but I guess that's what the RS1 is for.
I feel like the RS2i is more suited with comfie pads from the 90's that are much closer to the ear than today's comfie pads. The midrange is much fuller as well as the bass presence. It makes a massive difference to the whole sound presentation. No longer do I hear a weaker and bright sounding headphone compared to the RS1. What I heard is a more forward midrange with great vocals and full body midbass. I am not sure where these comfie pads can be obtained as I have them from my headphones that are quite old. The old comfie pads do not sound the same as modern day comfie pads at all; modern comfies sound pretty much the same as with bowl pads.