Pros: bass, resolution
Cons: design, coloration
These were recommended to me in the forum when I was searching for a "warm comfortable IEM". Eventually I got them from the sale/trade forum in a "like new" state.
The build quality is quite poor on these. The dirt filter on the left nozzle was misplaced slightly, not fully covering the nozzle. This could be easily fixed by slightly elevating it with a needle. Also, one of the bass filters came off (or was never fully on) which is also very easily fixed. However, it's recommended to take a thorough look at them before trying them out, as especially the loose bass filter produced a very awkward sound.
The metal body and the stiff cable seem like they'll last for a very long time, though.
Initially I also had huge comfort issues. The screwable bass plates touched my ear which is very uncomfortable and after some time even hurt. The included silicone tips are too hard, in my opinion. Thus I've replaced them with an easy DIY foam mod. Rarely, the plates still touch my right ear, but it's nothing major and can be prevented when wearing the cable over-ear.
At first I had a very hard time adapting to these as I'm used to the Ultrasone HFI-780. The warm sound signature and strong boomy bass of the Hippo was very unusual to me. Meanwhile, I think they're a great addition to my collection and I wear them every night at very low volumes.
I'll make this short as this is my third review today: These IEMs are awesome with Hip-Hop/Rap, Electronica and Rock. Bass is a treat (punchy and boomy at the same time, slightly bloated - extends just slightly into the mids but very fair for the price), resolution is great and soundstage is amazing for an IEM. The highs extend far enough and are very sharp (in a positive way). Incredible value for the price!
This IEM is pure fun and not recommended for analytical listeners as the sound is colored and slightly too dark.
This is a great back-up IEM. Sadly I can't fully recommend it as first choice because the sound signature is a liitle too far on the "fun" ("musical", if you have to) side.
Hippo should invest some bucks in a product designer for future releases. The overall design is nothing but practical and the "hippo VB" prints already look like fakes.