I have a blue defy 21 (skeleton), got it about a year and a half ago. I did a basic review of the watch last year. I still love it, I wear it daily and it is comfortable and light - note the watch has no bracelet micro-adjustment so it could be tricky to get a perfect fit. It has held up well in daily wear, the bracelet has some marks and scratches but the titanium hides these well. I got mine from a Chrono 24 seller as my local AD would not budge much on the RRP, this may not be the case at the moment with COVID. I do not think they ever sold that well and it is a very niche watch that will not appeal to everyone. I have no plans to sell it and will keep it as my daily for the next few years or more.
If you need any specific info let me know.
It did develop a fault with the chrono function, where as the minute totaliser would not move unless nudged. I sent it back to Zenith, it took a few months as it needed to go back to their head office but communication was good, and I was happy with the service.