I would say overall 4 ohm is less bright. I've tried all the different options and have found an 8 ohm cabinet is brighter running at 8 ohms than at 4 ohms. I run 2, 1X12, 8 ohm cabinets, one open back EV and the other a thiele C90 at 4 ohms and to me that is the sound I prefer over a single 2X12 running at 8 ohms. I used 2, 4X12 cabinets for years in the 80's & 90's because they sounded better together verses just one 4X12, plus I could hear the sound better having a speaker pointing at the back of my head, not just my knees. The 60 watt option is something I try and always switch back to 100. I've done that forever with every amp I've owned. I have never been a player who liked low wattage amps for some reason. That reason is I either perform or practice with bands several times a week and consider myself an amp player more than a guitar player, it goes with being an entertainer first and foremost as seen in my videos.