While all fitear customs are very good, there are obvious differences (obvious, not significant) between models. Amongst 435, 334 and 335 for example. I find 435 the easiest on the ears, 334 very pleasant and the 335 immediately impressive but probably can lead to fatique a bit easier after an hour or so of listening.
I find 334 a good balance between 435 and 335 but purists should go for 435 and 335 will give the most impact.
In any case, I think all of them are great choices!
Thank you. Maybe I should wait until fitear releases its new product.