Collet size is the first decision because it fixes what the grinder will hold. A 3mm collet takes the small burrs and points used for detail work, a 6mm collet takes the larger ones. Nothing else about the tool changes that, and a point bought for the wrong collet will not fit at all.
Free speed follows collet size. The micro tools reach 58000rpm because a small burr needs speed to cut, and the larger bodies run slower with more torque behind them. Free speed is stated on 98 of the 107 lines here and weight on 101, so a tool can be compared on both before it is bought.
Head form decides access. A straight body runs the point in line with the hand and suits open work. A 90 degree head turns the point sideways for a face that cannot be approached head on. Long reach bodies at 260mm put the point deep into a casting or a chassis rail, and micro and mini bodies fit where a full size grinder will not enter. A micro body and a long reach body are not interchangeable even at the same collet size, because one is chosen for entry and the other for depth, and the point they hold is the same.
Kits supplied with grinding points sit on the same leaf, which suits a first purchase where the points are not already owned and the collet size is being fixed for the first time. The Chicago Pneumatic CP3000 ladder runs through the middle of the range, with the Sealey Generation and Premier bodies alongside. Anything unresolved goes over WhatsApp on 07754288583 with a photo of the point being used. The Sykes BIONIGRIP and Mueller micro bodies sit at the fine end of the range where access matters more than removal rate.