I don't personally have any SUPER high-end glass, although I do have the Sheldon Black Concentrator that retails for about $180, as well as a recycler from Cory Glass that's in the $150-$200 range. I have a mid-range bubbler from Glass Blowers Direct, the inline submarine bub that retails for $110. Then I have the D020 and the TKO, for cheaper glass (I have a couple other pieces, but the above reflects my "regular" lineup).
It's hard to say what I use the "most" because I do go through phases. I will say that given the choice, I wouldn't choose to dab with the TKO over either the recycler or the SB--the other two do feel like a more "quality" experience. I even enjoy dabbing through the GBD piece over the TKO. That said, the TKO is an awesome size to carry around the house and, at the price, I have no fear doing so. I usually dab in a fairly "safe" zone in my room over carpet, but when I don't, I most often choose the TKO.
As for flowers, I do most often use the D020. I also enjoy using the GBD inline with my Lotus, and have also used the recycler with the Lotus (even though it's a DI piece). I really don't have any high-end pieces appropriate for flowers, so it's hard to say if a high-end piece could easily dethrone the D020. I will say that I've tried two other AliEx pieces from Kathy's store, a honeycomb bubbler and a honeycomb to eight-arm bubbler (or something...it was a friend's piece), that I really didn't care much for. The honeycomb in particular just had too much restriction and was built crooked and was therefore not all that functional.
My thoughts are that the couple of higher-end pieces I've tried DO feel higher-end than the cheap Chinese glass I've tried. That doesn't mean that the Chinese glass can't be perfectly functional, and in some cases, quite nice. It just means that these Chinese pieces are not exactly indistinguishable from their higher-end counterparts. Also, these Chinese bubblers, while nice and a great value and, honestly, a fantastic addition to anyone's collection solely for the purpose of having glass that you can break without crying, aren't nearly as innovative, unique, and just plain fun-to-use as a lot of the higher-end stuff out there.
I see a place for both categories of glass in most vaporists' collections. I'm not sure that I'll personally ever spend $300+ on a piece of glass, unless my disposable income increases dramatically, but I'm not content to stick to $30 Chinese bubblers, either.