Yeah, Convoy is supposedly better quality than KD, but I don’t have one myself. The XinTD c8 from intl outdoor is supposed to be the highest quality c8 around. I do have a xinTD and it is worth every penny and more IMO.
The KD is known to be very bright for the price. Some members have also had good experience with Lightmalls xml2 c8 and c12 (myself included). Lightmalls xml2 seem to be a little bit brighter than KD according to most reports.
Cheapest bang for buck I would go lightmalls. Ultimate best overall and best longterm value is still the xinTD.
Read this post and this thread here for more info:
https://budgetlightforum.com/t/-/17353?page=1#comment-400943
Hope that helps.