So, after owning the ER4PT for a little over a year now, I wanted to weigh in on some of my opinions (I guess this is like a mini-review).
When I first started using them, I went through all the tips that Ety offered, and even got some of the Shure foam tips to see which ones I liked the best. In the end (after about a month of testing), I found the Ety triple flanges to sound the best, but they were really uncomfortable. So for about 2 months I used the Shure foam tips since they were a little bit more comfortable, but I eventually gravitated to the triple flanges full time. I use my headphones daily, for about 3-4 hours a day, and id say for about 2-3 months I found them to hurt my ears quite a bit while wearing them for 3 or 4 consecutive days in a row. I knew going in that people said these werent very comfortable, and coming from the Westone 4, I used to agree. I was close to buying new IEMs as a daily driver, but my funds were short so I decided against it since these werent cheap to begin with.
After maybe 6 months of 5 days a week use, my ears got used to these phones and all of a sudden I realized that I was no longer having comfort complaints; on the contrary, I even found them comfortable to wear for hours on end. Even un-broken in triple flanges feel comfortable, and I can wear this headphone as long as I want to listen to music, audiobooks, or podcasts without any discomfort AT ALL. I dont know exactly how long it took for me to get used to them (my ears used to get really sore, and it would hurt to pull them in and out), but I can attest to the fact that if you enjoy the sound of these IEMs as much as I did/do, that you can[i/] get used to them. To me, they are now almost as comfortable as my Westone 4s, and just as comfortable as my previous Shure SE315s.
As for proper insertion, it definitely takes a while to find the balance between being too deep and being too shallow. My right ear sounds better when it is inserted almost as far as it can go, while my left ear leaks slightly when I go that deep and have to pull it out a little to find the perfect seal. A pair of tips can reliably last me for probably 3 or 4 months, and after that I have to rotate the tip in just right way where the creases line up towards the bottom of my ear, but I can still get a decent seal for probably another month. Finding the perfect insertion still takes me probably 5 or 6 seconds for the left ear, but my right ear inserts perfectly almost every time.
I am currently using the red filters (as per luisdent's suggestion), and in using these I definitely liked the subtle changes that they provided better. I havent changed them out for about 10 months now, so I dont even remember how the blues sound anymore. Im completely happy with the way they sound, and im not looking for any difference atm (other than the horrible SQ out of my current Moto X smartphone - otherwise my rockboxed ipod classic sounds much better - especially with the S adapter and maybe some EQ). Sure, maybe everything about the sound isnt perfect, but still by far my favorite IEM out of any ive owned in the past.
One last thing, cable noise. At first, I was extremely bothered by the cable noise when moving around, and was considering making an aftermarket cable for them. But after the suggestion of wrapping the cord around the ear, I found that the noise was eliminated almost entirely. It's a shame that they arent ergonomically set up for wearing them this way, but the twisted cable is flexible enough for this to be a non-issue. My one and only complaint about this IEM is that the cable is just too long. I always have to stuff a coiled up piece of it into my pocket, or else it gets caught on things. Unless you are 7 foot tall, this cable is just a little too long.
So in short, my long term experience with the ER4 is extremely positive. This IEM did have quite a steep learning curve, but im glad that I roughed it out.