Like Steve, I have the Fathom 40. I liked them so much I bought 2. What is there not to like about those reels? 25lbs of drag easy. All metal construction. Fairly light weight. Incredible free spool. Sits low on the rod so it doesn't feel like a 40 sized reel. If only they came magged.
I think I cast fairly well with them, but backlashes are inevitable. I was originally an all mono guy, then tried all braid after so many others do it. A few backlashes later and I do braid backing with typically 100yds or more of mono topshot. Much happier with this configuration.
I'll do some research in regards to magging a reel. Too fearful to "f" with a perfectly good reel until I'm educated enough. Be nice to see a tutorial.
As far as how to keep the spool from slipping, I have used that blue tape (can't remember the name) that's very stretchy and is texturized. I use from time to time when throwing irons. It helps a little. I found the best thing for me is to keep the hand I use to hold the reel, in my case my left hand, dry as much as possible to aid in anti slipping.
I think Binh wants to see if someone has a magged reel he hasn't heard of yet. Sorry Binh, there isn't too many large and "modern" magged reels out there other than Avet that I know of. I do know of older ones from the 80s and 90s in a 30 and 40 size reel. The hard part is finding one.