get the Zowie EC1-A or the EC2-A depending on your handsize and gripstyle
(plamgrip and larger than 19cm hands? EC1-A / for any other gripstyle and handsize EC2-A)
i also played around a year or more with my G502 and the xim but lately i upgraded to the EC1-A
the difference is huge, the shape fits your hand much better and also the mouse is much lighter
overall it greatly increases your accuracy
the Zowie doesnt need a driver and has 3200 dpi so perfect for the xim

alternatively the G403 which i would say from a technical point of view is the best xim mouse right now
overall i recommend you to watch the following video to be updated on whats currently available and whats worthy to look into
https://www.youtube.com/watch?v=-J14fyar5ns