Some of us got this Sennheiser IE 200 back in February 2023 and since then they've regularly had discounts/sales with it on Amazon. A few people have said it's been below $100 (instead of the $150 launch price) or even at $90 or so regularly, check Keepa/CamelCamelCamel/etc. for the price history and deal alerts.
For those complaining about cables, just get the "Audiohive MMCX TO MMCX for N5005, IE 300, IE 600, IE900" adapter/converter" from CKLewis Audio Store: https://ALIEXPRESS/item/1005005445306949.html.
And then it should work with a lot of MMCX cables. I use it with my FiiO UTWS5 (still can't believe FiiO discontinued the UTWS5 without the UTWS15/etc. or its successor available yet) and it's really good and secure. It doesn't make the IE 200 cut out, unlike the other N5005 and IE 300/600/900 converters, just make sure to fully plug in the adapter/converter, you should hear a loud click of some sort.
More info on the Sennheiser IE 200, DIY IE 900, MMCX to MMCX for N5005, IE 300, IE 600, IE900 adapter/converter, et cetera: https://www.reddit.com/r/HeadphoneAdvice/comments/14vm7ly/sennheiser_ie_600_alternatives/jrfbo45/
For the bass, some people are trolling about the hole in the nozzle of the IE 200. As long as you don't use the stock Sennheiser ear tips or so, it shouldn't be a problem.
Spinfits are like $10. FiiO HS18 is $5, often cheaper during AliExpress sales from FiiO's Official Store (FiiO HS19 is out of stock at the moment). Those will alleviate any bass leakage issues, no need to use tape or anything.
The (sub)bass will hit hard but the driver size and tuning may make it feel lacking for some.
To really seal the bass or increase it, use Final Audio E ear tips (they add more bass and/or reduce the treble), it should be $15 for the 5-sizes multipack on Amazon.
Final Audio E have a smaller opening for its stem/core and so it's pretty tight on the IE 200's nozzle. With wider nozzle IEMs, the Final Audio E will actually bounce off the nozzle if you don't put it on quickly/properly, so ya that tension is perfect for IE 200.
More info on Raptgo Adaptive ear tips, Audiosense S400, ddHiFi ST35, Final Audio E Clear/Red or 2020 Edition, and Spinfit CP155 ear tips: https://www.reddit.com/r/headphones/comments/11pyujp/eartips_similar_to_the_ones_included_on_the_hbb_x/jc1b41g/ and https://www.reddit.com/r/headphones/comments/13f6j7m/am_i_crazy/jjv10r9/
Conversely, if you want to reduce the bass (lol), use TRI Clarion, it's like $10 too on Amazon. I only use TRI Clarion on IEMs that have overwhelming bass (think all the way to the ear/pinna gain or ~800Hz), it will probably let the vocals through no matter what.
Ear tips, noise reduction, comfortable IEMs and nozzles with small ears, et cetera: https://www.reddit.com/r/headphones/comments/14uzhh8/ear_canal_stretched/jrbrpwy/
These days thankfully ear tips are being graphed (due to different insertion depth, nozzle length, nozzle angle, etc. it's not gonna be the same experience even with the graphs) on squig.link and so on. And as such you can see how the Final Audio E is a consistent outlier for the treble/etc. areas.
MD Jacques with the KZ Castor Bass Version and Final Audio E with other ear tips: https://www.youtube.com/watch?v=ZWZIQ3fFr7E&t=132s
The IE 200 will need more volume, so just a few presses up your regular range. Since some people will think there's no soundstage, vocals, et cetera, and in reality you don't really need a dongle/amp/et cetera.
You only need to increase the volume a bit on the phone/PC/app as you'll immediately notice that the IE 200 is low volume if you were listening to a different IEM beforehand. Some people like crinacle and myself listen at around 50-60dB or so (for testing IEMs some people go up to 70-80dB), and that's why some people feel like the IE 200 is underwhelming as they forget to adjust their volume levels.
Oh and unfortunately, even with the UTWS5 TWS adapter or aftermarket cables, the plastic shell of the IE 200 will produce a lot of noise (echo) if you are touching it with your hand or something like that.
Some people eat/talk/etc. while using their IEMs (try not to do that especially if it has the vacuum seal, especially when eating potato chips, lmao), and so that's why you hear people complain about the microphonics/etc. of the IE 200 shell. Even if you try different ear tips, that plastic echoing or reverberation will remain. It's not really an issue if you are just listening to music but yes, compared to other IEMs it can be pretty noticeable if you're moving around or something like that.
Otherwise, for ergonomics or comfort, the IE 200 is super good. There's some newer ones recently with a similar flush or low profile design, like say NF Audio RA10, but these are not as well-known and so quality control may be good or bad (oh and people also talk about bad QC with Sennheiser IEMs).
There's always the bullet style IEMs if you want that hassle-free ergonomics. Only Etymotics and certain boutique/etc. Taobao/AliExpress IEMs go real deep, so it's easy to use wide/shallow ear tips with the common bullet style IEMs. Personally I still use say the taller Spinfit W1, CP145, and CP155 with bullet style IEMs, it works better for my ears.
There's now a massive database for bullet style IEMs on Head-Fi: https://www.head-fi.org/threads/the-bullet-cable-down-iem-database-140-update.964041/page-3