Hi Richard , I had the 14mm version of these and would still have it but I had the chance to buy a 14mm TV Radian , I found exactly what Bob says , these are a nice all round eyepiece , solid and well made with a diecent FOV , a definite step up from the generic plossls supplied with todays scopes , these plossls are mostly all good eyepieces by the way compared with what was available 20 years ago , we are spollt by choice these days .
On the 8.5 - 6.5 mm question as the fl's decrease in this size the jump in magnification jumps signifantly .
Brian.