I had a full set of Vixen LV's and I found the 20mm was as good as my 19mm Panoptic except the TV pan had a larger field of view that I liked .
The smaller focal length LV's were almost identical to my Radians , but I like the softer views the Radians give on the moon and planets , especially in my Tak M210 .
Its really down to personal choice , I found the Vixens excellent in all ways .
I would have kept the Vixen's in a heart beat but I decided my TV's were the ones to keep , my personal choice .
Brian.