These are going to be my first dip into pro-ish level in ear monitors. When it came to other iem's that I have tried, I have only ever bought consumer level in-ears and some of the budget oriented monitors from KZ like the ES4 and ZSN Pro X. This is actually my first Sennheiser as well so I was rather excited due to the company's lineage and experience.Inside the box was nicely laid out and came with everything I needed. The only gripe I had was the little "bag" that was meant to hold the iems in. It's one of those "snap bags" but instead of having a magnetic clasp to keep them closed, its just two bits of stiff plastic that keep it closed by simply being rigid, and if you want to open the bag you push in the sides to snap it open. They really should have included a zippered bag of some kind because that would have been simpler.The comfort of the monitors is simply great. They're small and could fit into most ears and the stiff over ear hook can easily be bent into any shape to fit any ear. Some might not like the wire design but I think it works out just fine. One very important thing to note about the silicone and foam ear tips is the cylinder of foam on the inside. Please take care when switching out tips because this foam is CRUCIAL to keeping the sound profile right. Yes, even though you can swap out the tips for more comfortable ones, you will have a VASTLY different sound profile due to the lack of dampening foam. Also, be sure to double check the nozzle itself because it too has some foam inside. For the most part, just be careful when switching tip sizes and use the cleaning tool to orient the tubes of foam so they sit correctly inside the nozzle and ear tips. I know it sounds like a hassle, but once you are aware of it, there should be no issues.For the sound quality. I have to say that these things are well balanced with some boost in the trebles that add a bit of brightness to each song. Snare drums and cymbals sound a bit more forward, but this is where the small fault comes in. There will be some songs in which the "S" and "T" sounds from vocalists will be a bit harsh, but not unbearable. Think about how recording a voice sounds like without a pop filter and you will get the general idea of what I'm talking about. This doesn't mean the sound is totally bad, far from it. It's just a warning that some tracks with certain lyrics will not sound the best unless the mastering of said track is a bit warmer. I have tried many genre's with these monitors and I will say all of them are pleasing and detailed. Even the bass is well tuned and you can get a nice thump, nothing that is head rocking and muddy but good enough. I will say that these do fit within the pro range and have a rather flat curve, in spite of what you might see on some frequency response graphs. I will say that minus the occasional shrill tracks you might run into, these will fit most, if not all genres of music.In the end, these are indeed pro level in-ears that you can get for a mere $100 and they will not disappoint. If you want to hear familiar tracks in a different way, I would recommend these. But also be sure that you are listening to a good source because the clarity of these in-ears will reveal badly recorded or low quality sound files very easily. A definite must-have for music enjoyers.