Oddly enough, the qc15 is the only product of Bose that I think they did a decent job with. When it comes to NC cans, they are comfy while having good cancelation. The sq isn't bad either. When it comes time that you want good nc cans, sq can take a slight backseat compared to comfort and nc. That is exactly what the qc15 provides.
OK sq, high comfort, high nc.
For me personally, non of the noise attenuating ear products under 100$ were comfortable for the long haul. Iems make my ear canal sore and I hate microphonics and skeletal noise propagation. The sealed cans squeezed my head too much such that it hurt. Anything that I found comfortable for the long haul had little to no sound attenuation like the denon d2000 but had excellent sq. The Bose is the only sound solution that is comfy enough for me while offering good attenuation and OK sq.
Mt advice to you if you are forced to only spend 100$ is to try a 100$ iem that comes with several ear fittings. Perhaps the klipsch s4. My issue with the s4 is that my ear canals do not appear to be the same size. Medium fits my left ear, but the small is too loose for my right ear while medium doesn't even fit into the canal. YMMV
I have wasted enough money on this hobby to know that it doesn't matter how much the earphone costs. If it isn't comfortable, it doesn't get used. Plain and simple. You know you like theqc15 because you were able to audition them. Knowing what I know now after these years, I would buy them if I were in your shoes. Life is too short to waste time messing with products that might be as good as the one you know you like. Just save up and go for the jugular. Since the qc15 seems to have passed your audition, just buy it and be happy and know that you will enjoy it for years. I have too many 100$ samples that fill up my drawers because they were enjoyed for days. I would have saved a ton of money if I just splurged the first time and bought the 300$ pair in the first place.