The UE-10 Pro might be overrated for the audiophile who can just get excellent sound in $200-etymotic phones. But for the monitor engineer and performing musician, the UE-10 Pro's price tag is not all that unreasonable given the excellent sound quality and additional headroom, construction, reliability/dependability of the product. The UE-10 Pro alone has 6 drivers. The ER4 has only 2.
The V6/7506 might be overrated for some simply because they are using it wrong. These are great monitoring headphones that I use for editing. They are intended to be bright, but better than any other headphone is the bass response. They are an indespensible tool in the studio and for $69.99 they are hardly overrated. They are also one of the sturdiest phones I have ever owned and I still use my 12 year old V6 constantly-maybe not to enjoy music, but to do editing. Again, for the consumer, these phones might not be all that, but just to say that they are overrated is simply stupid.
If I had to point to an overrated phone, that would have to be the Shure E5. It uses two drivers and a crossover to divide the lows from the highs. The intent was to provide crisp highs and strong bass. In reality it only provides strong bass. The mids are muddy and the highs are missing. Also, because of the high sensitivity of these phones, they tend to pickup and amplify noise in noisy portable players, which tends to destroy the listening experience of the music at low volumes. As IEMs, they isolate noise to up to 20dB, which is mediocre. Sensa's and UE's IEM isolate to up to 26dB.