For me, personally that's really hard to do, since I like both of their sound signatures and the uniqueness of it. It's all about preference from this point. They are both good and unique in their own way and can only say.....I'm glad I own both!
This is what I can say for each, though.....
The HLSX-808 (Titanium driver & AFX BA hybrid) has deep sounding bass with great impact, and clean and clear vocals joined with crisp hi-end details. Soundstage is big and spacious, which brings out the best out of most songs effortlessly.
The VIVO XE800 (Dynamic Driver) has a superb soundstage with life-like vocals and excellent details from end to end without ever sounding harsh or sibilant (depending on your source) with mirror-like
similarities in SQ when compared to the GR07.
Hope this helps.....