Joined the community of IE-300 owners several weeks ago, after discovering that I misplaced my pair of IE80's and looking to purchase a replacement. I was aware that the IE80 was discontinued and replaced by the IE80s, but reading so many negative reviews, I was discouraged to go for it. Than I discovered the new crop of 100s, and the attractive discounted price of the IE-300 ($199 Amazon) made me to pull the trigger. I was pleasantly surprised, that Sennheiser finally got to their senses, and packaged this product with economy on mind, rather than over-engineering it. The earlier lineup of yhe IE8-IE80's carrying case was practically useless, making the process too complicated to put the earpieces back into the case, that's why I found it empty a year or two later, when I craved the gear after a very long break from them.
I'm surprised about the high volume of negative remarks regarding the 300's cable, personally I find them very comfortable and high quality, though I don't move around too much while listening music. The factory installed gels also work perfectly for me, I'm floored by the effectiveness of their ambient sound isolation, and opened the paper bag with the tip assortment just to see the content of it. These are so far the best in that regard I ever owned, as well as comfort. Kudos to the design team for nailing the ergonomics of the ear places to this level of perfection, I'm amazed.
Regarding sound performance, to my surprise they perform exactly as I expected of them. Coming from the Logitech UE900s, my most favorite gear of all time, I knew this gear would not be able to match their resolution, but fortunately they not that far behind. While surely resolution will not win accolades for Sennheiser, I don't think it would be realistic to expect more in this price range. The purpose behind this acquisition was to have a pair of wired IEMs for everyday casual use, and they fit the bill. Wish at least the bass resolution would be a tad-bit higher, but I'm glad to hear the drowning mid-bass hump of the IE80's gone. I have not owned a single pair of IEMs ever, that would match the mouth watering fast, deep and detailed bass of the UE900s, not even the Westone 40SE. That said, I'm still very happy with the purchase, and I hope it's sound performance will improve with more burn-in. So far I have less than 24 hours on them. Since I listen exclusively Sounds From The Ground like trippy electronic music, the recessed mid-range is a boon to me.
As I was reading through all the comments, I noticed many of you also owners of the IE-100 Pro. I picked up a pair a long time ago for monitoring sound recording, I never ever attempted to use them for music listening, I did not expect they would be suitable for that purpose. You folks got me curious now to try them, once I'll find the time, after finish burning these in, or get bored with them....