Bearings are generally a matter of debate amongst players that I know. Some say it doesn't matter really, others say it makes a big difference. IMO the most important thing is that the bearings be serviceable so you can clean, wash and lubricate them. I personally have not found a big difference in bearings so long as they are clean and well maintained, so I just get the cheapest bearings that are serviceable and I clean them when I rotate wheels and wash/lube them every so often. Good technique, strong skating, well-fitting skates and the proper wheel make much more of a difference for speed, agility and control.
Re the quality of Konixx, I think they make excellent wheels. I'm sure these bearings are good bearings. Despite the marketing, I'm not convinced that good bearings translate to a better or faster skater.