Did you actually read the 17D thread? Have you seen all the people with swiss cheese internals, sometimes squishy, sometimes not frame walls, sometimes clean inside, sometimes trash AF, poor customer support, and so on?
The X21 is the same open mould as my LTK 268. I can tell you i'm not swapping mine for a LC 17D 
I just hope that when u make a mistake/when a problem appears in your work you don't get tagged with that... I've seem people complain literally about every brand here in the forum so...
Hey!
I am riding the Tantan X-21 Frame since about three years and I am still quite happy with it. Made some changes (headset/Bb) and know it is pretty straight forward.
Since all the hype about the lcr017 Frame and the good reputation of lightcarbon I am considering a change of the Frames and Cockpits.
Do you think the change is worth it?
Thank you!
Anyway, and just to complement my "No" from before. If you are happy and fit well with your current frame, changing for the sake of changing doesn't make sense. You won't get much advantage from it. Whether you
want a new frame. Don't try to justify it logically
Want is a good enough justification
