Hey folks, I recently purchased the E8's and wanted to add my experiences so far. I owned a pair of Sennheiser momentum true wireless a month or so back, so most of my thoughts are in terms of how the two IEM's compare.
Sound: so far I'm really impressed with the E8. Some reviews i'd seen gave the impression the E8 sound was only so-so and not in the same league as the MTW. This has not been my experience at all - although I haven't tested them back to back I would say, in terms of sound, they are quite comparable. Similarly large sound stage and an overall full sound with decent clarity. From memory, I feel like the MTW might have felt more full whereas the E8 is a bit more detailed. But for me there's really not a lot in it. They both sound great for day to day use.
I had heard some mention that the E8 and/or MTW were too quiet or lacked bass. For me, they're both fine. I would typically listen to these IEM's with my iPhone 8 at 50-70%. Occasionally I might crank a song on max, but it quickly starts to feel uncomfortable, so its not something i'd do often and I never find myself wishing I could go louder.
The bass criticism is a little more understandable for certain people. I would consider the E8 and MTW to have quite a neutral sound where the bass is definitely present, but not over-emphasized. You can enhance it a little using the software, but if you like huuuuge bass that's not as much of an option here, so perhaps I can understand if bassheads might look elsewhere.
Comfort: The E8's and MTW's have a similar physical shape, but the E8's are a bit more rounded and notably less bulky. In my case this is the difference between being able to fit the IEM's inside my motorbike helmet for commuting. The E8's are a bit tricky to get my helmet over, but otherwise pretty comfortable, while the MTW's due to their size either don't fit or are painfully forced into my ear. This scenario obviously won't apply to many people, but its one example of a larger unit having less utility.
The E8's also come with a wider range of tips, so where the MTW's XS was still too big for me, with the E8 both S and XS were acceptable. In addition, the E8's include a medium comply isolation tip. After much experimentation I decided this was actually a bit too big, but because of the range of options given with the E8 I had enough information to know what to try next. I picked up a pack of small comply tips and they've been fantastic!
Connection: With the 5.6.0 firmware a lot of the E8's biggest issues appear to be resolved, but I definitely still experienced a few niggles. Most notably the E8's can be a little slow to connect - after putting them on there's several seconds of tapping the button and checking my phone before they come alive. On a couple of occasions I've resorted to returning them to the case to see if that resets them, but this is happening less as I get used to the E8's quirks.
The E8's also clip here and there, I assume from interference - you experience a split second cut out in whatever you're listening to. This seems to be very dependent on environment, since I get a bit more of it at home, whereas at work or commuting it happens very little. Its not a deal breaker, but its definitely annoying so fingers crossed this gets fixed in a future firmware update.
In my experience, the MTW's didn't have any of these issues. They connected instantaneously without even needing to push buttons, and I can't remember them clipping at all the way the E8's do. In addition the MTW's seemed to have a slightly better range - I could go almost to the other end of my yard (10m?) while leaving my phone charging in the window. With the E8's I have to stay a lot closer, but this is not a hard thing to work around.
Transparency: This is a feature that works seamlessly on the MTW, but is a little hit and miss on the E8. The MTW's reproduction of background sounds is so good you sometimes forget its coming through a microphone. In contrast the E8 can have this bizarre digitized representation of the world where near and far sounds are mixed up and random sounds like crinkling paper get ultra boosted. Less complex environments such as an office are more passable than others. Playing around with the transparency level can also help.
In practice I use this feature sparingly on either IEM. It can occasionally help in case you didn't realize someone is talking to you, but since I still prefer to take out either earphones to have an actual conversation, the advantage of the MTW somewhat cancels out.
Controls: I slightly prefer the E8's controls. The MTW tries to keep all playback controls on one side, but this means using the always finicky triple-tap for going back a track. The volume controls on the MTW are also a little too responsive.
Design: The design of both the E8 and MTW is quite similar, but the contrast of polished plastic and matte rubber on the E8 has a higher quality feel, whereas the MTW feels overly plastic-y. The logo on the E8, is also a lot more subtle compared to the chrome-sticker looking Sennheiser logo, but this is a personal preference. The charging cases for both IEM's look great, but the leather finish of the E8 seems the more durable and cleanable of the two.
Battery: I understand the E8 has slightly better battery life than the MTW, but this wasn't an issue for me with either IEM.
Microphone: I didn't bother testing the microphone. Since I take few phone calls this is not a critical factor, but my expectations for a tiny microphone that far from my mouth are pretty low.
In summary, very happy with the E8. If the bulkiness of the MTW was not a concern, many people might prefer it over the E8, particularly due to having less connectivity issues. The E8 is typically a bit cheaper and I prefer its design, but the main reason I would take it over the MTW is comfort. Due to its compact design I can wear it more comfortably for a wider range of day to day applications.
