Some amps react differently for the drives. For instance my Redplate amp with KT88's, and according to some others, their Redplate amps are more picky as well. I noticed that as I added back midrange in the clean channel on the amp using the 6 position rotary (Blackface 1, Blackface 2, Brownface 1, Brownface 2, Tweed 1, Tweed 2 (more midrange toward the right progressively)) the FX8 drives sounded better. Throwing the preamp compression switch in the back helped even more. Unfortunately my favorite clean sound is on Blackface 1 with preamp compression off. However, the Redplate distortion itself has never completely been my cup of tee, it doing way better low gain than higher gain boosted JCM 800 sounds unless I again throw the preamp compression switch which compromises the clean.
However I think the Redplate clean with compression on may still beat or equal any amp switcher in the clean department (possibly in subjective opinion) but the clean with compression off is magical and the number one reason I don't sell the amp. Somehow the FX8 drives are more fidgety to setup within those parameters (a bit more so than analog drive pedals). However the FX8 drives are miles and light-years ahead of other digital units I have tried, you just need to play around with them as the presets didn't get me too far. And as I said, I suspect it is the amp itself that is harder on drives (though analog drives do have an advantage in ease of use.)
One thing that helped me was I turned off the noise gate in the presets as I don't go that crazy with distortion and some of the stuff I didn't like was how it was choking on static created by brushing up against the strings. Also, I have tried the Boss Gt-100 in 4cm with the Redplate in it choked my amp tone too much. I love how transparent the FX8 is.
I used to have an Axe II three years ago and I liked how it sounded in my Mesa Mark V in the loop, but I never 4cm'd it to see how it did in that department. If I didn't need to channel switch, since I couldn't afford an MFC, sometimes I would just plug the Axe straight into the Mark V power amp and use the amp sims and effects. It wasn't 4cm, but I had no issues with noise or tone. However everything changes one use your own amps preamp in the chain so I can't compare how it would have done in that department. Compared to Boss and Line 6 stuff I've 4cm'd before, the FX8 is the first device that is no hassle and doesn't have me disconnecting the cables to go direct in out of tone suck frustration. I love how transparent it is for 4cm.
But back on topic, I do need to try the drives with my BE100. I imagine the voicing of it's clean channel would work much better than the Redplate's high bandwidth blackface mid-scooped completely uncompressed clean. As I don't have much time lately, the Redplate is my practice rig with the FX8 connected, while my BE100 stays packed up ready to take to gigs with my pedal board. Once I get more familiar with the FX8 and have time to program it for our setlist I'll start to take it too gigs with the BE100. I'm in no hurry, my pedal board sounds great, but I look forward to the added variety the FX8 will give me, including many effects I don't currently have on my PB like delay, flanger, and phaser.
Edit: I do think I love the BE100' clean more than the RP's clean with compression on, while I dig the RP's clean more with compression off. Thing is, the BE has those magical mids. Problem with the Redplate is that when you add back mids by getting into the tweed clean settings, it can also get kind of harsh, like there are too many frequencies. The Marshall style low cut and high cut really does create the perfect platter for stacking all drive sounds and voicing mids for me.
