A little late to the party but I've had many of the IEMs listed in this thread and have some Sony XB90ex coming.
Hippo VB: [Good
review]
Very very good bass IMHO. So good I had 4 of them at one point in time. I used them for most mobile activities (Hoops shootarounds, running, yardwork) and NEVER had an issue. After time one was left on a plane by one of my daughters the other was lost, One did get ripped(purely an accident) and now the lone survivor is a dinosaur since Jaben Audio doesn't seem to have any more. They had 3 sets of discs or "bass ports" to adjust the bass as you would like and I felt that at least this was good for simply the option. I am a basshead thus I used the set that created the bassiest sound. Now there is
this guy who feels very strongly against the Hippo VBs but I have to say, even though he does have a generally correct point that the build
COULD be a bit better I had used my Hippos regulary at the Gym during shootarounds and running and still never had issues. I used it with an iPod mini and armband where I would tuck it in the shirt then extend the cord out of the left tank armhole then under the band and to the mini port with enough slack where I could raise my arm to shoot without hindrance. No problems over YEARS of usage (last pair of Hippos I purchased was in 2014 and the final pair is still working).
GR07 Bass Edition:
I had them, did appreciate them, and figured to get some more but then
ONE month after they were being used one of the pieces stopped working (Left I believe). I
NEVER used them for activities and simply had them as computer buds. I don't remember them being tugged, jolted or dropped in any adverse way.
As far as the BASS it was clean(er) than the Hippo VBs if ever so slightly and the mids and highs were "crisp" and precise but if only they would have been more durable.
Klipsch S4:
I have had two pair of these over time as once again one pair was left on a plane (people that work for US Airways have gotten some great gifts). Still I would say that these have been appropriately rated below the Hippos and other competitors.
The Bass was clean but almost hindered. The mids and highs were clean but not smooth like the GR07s and not enough of a difference for me to use them more than the Hippos. This
Shoutout is an apt comparison of three IEMs that I feel addresses the pros and cons of each set fairly
SRE 215-K:
I decided against these in favor of the Audio Technica ATHCKS77BK (2014) which I still use for general usage (non activities, computer, trips). They are decent general usage IEMs. So I cannot speak to the SREs since these were $30 more and reviews in general were good but not gushing.
Sony XB90ex:
These are being delievered this month. I am excited to see whether the glowing reviews and comments are true of these and I still have a Hippo VB to compare it to so IF folks are interested I can comment on whether I think they are better, equal or worse than the Hippos.