I can vouch for the NISMO ones - they fit absolutely perfectly
The Varis ones, while close, did not fit nearly as well (I used to have them on my car) - never quite lined up as it should have.
With the ebay ones its essentially a crap shoot - some might be fine, and last forever, others might not. We have a local customer who got some and within a years time, his yellowed and blistered and the epoxy oozed out...not fun stuff to get off your paint! Conversely, mine have last through winters, hot summer heat, rain, etc without incident