I have the w30 and w60. If you like the w30 sound signature then the W60 is the obvious upgrade. Putting them next to each other they both have similar overall bass emphasis but the W60 is quicker and has an overall clearer and holographic presentation of the mids.
I only just received my m9 in the Aussie A2A special ($899AUD) so I am still planning with tips and using it as my daily driver.
Moving from the w30 to m9 is an upgrade as expected but the main thing I think you will notice is the 'clearer' mids which I attribute the reduced lower mids and the overall higher treble.
I would not consider the ier m9 such a leap over the W60 and I think at this level there is much more subjectivity for user fr preference. The w60 has a higher bass 'shelf' to my ears and would consider them bassier across the range over the m9. The m9 had a more forward mid range (upper mid) but I would not consider it forward like my Fiio fh3.
The w60 has a more grand presentation in comparison to the more 'accurate' m9. Both provide ample detail retrieval and I find very musical.
As for a source, I am using mostly a Samsung galaxy s10e (shoot me now) so take that as you will.
I bought and sold the fiio BTR5 as even in USB mode there was no improvement to the smartphone. I listen at 3/4 volume when using the m9 compared to 1/2 volume with w60.
I use an Astell and Kern ak10 for desktop use and I hear a bit more 'crispness' to the presentation in comparison. The ak10 had plenty of power and I always ensure I turn it right down to 0 before plugging in my IEMs to avoid blowing my earphones/eardrums.
I am eager to try higher end sources but also sceptical about the actual improvements for iem use.
Comfort at the moment goes to the w60/w30 for me and I think this would be universal. They just pop in, give a seal instantly and disappear. I am getting a little bit of soreness with the m9 around the concha/entrance to ear canal. I have currently settled on my old ue900s silicone tips as they are short, soft and have a shallower and easily achieved seal. I find trying to get a deeper seal is uncomfortable and pushes the body of the iem too tightly against my ear however YMMV. I think my sensitive ears will adjust though and it may just be finding the right angle and/or tip. Fit wise these don't feel like they are going anywhere.
Another quick question to the masses regarding tip sizing with hybrid and TC: is the following acronym assumption correct ?
MS - medium SHORT
M - medium
ML - medium LONG
Apologies for including some of my initial random thoughts in this response.