Marantz vs Musical Fidelity

Hello if anyone's out there. This is my first time posting so I'm not totally sure if I've done this right. I'm wondering if anyone has any experience with Marantz and Musical Fidelity to be able to compare the two. I currently have both the PM8005 and the PM14-S1 and I find them to both be very enjoyable yet both have quite different characteristics. I've gone through I think 4 different pairs of speakers and this has always been the case. I've kept all other components and accessories consistent so it's not like I've been changing everything up and then I'm curious why there's no consistency or something.

The PM14-S1 is super attractive with unbelievable build quality and a very velvety wonderful sound and I love it very much. However, I feel like it lacks balls for some reason. I currently have Sonus Faber Sonetto II speakers which are 4ohm, so I know I'm drawing the full current from the amp. 

The issue is that the pm8005 is much more lively and responsive to volume changes. I can tap the volume on the remote or just slightly turn it on the unit and the volume increases very noticeably. The 14-S1 takes much more changes in the volume to be noticeable and I feel as if it doesn't play as loud or won't get as loud. This could be the volume number on the front of the 14-S1 getting into my head and me being scared of the number when I really just need to crank it up. I know the two volume styles have different circuitry and I shouldn't expect the same performance, however considering how much the pm8005 is outclassed by this big brother I guess I'm just expecting more? When I listen to a record for example, I have to turn the volume up into the -30's and that's not necessarily rocking the house or anyting either. Am I wrong to think that this is an issue? Should I be worried to turn the volume up regardless of what number is on the front?

I even shipped off the 14-S1 to be looked at and the technician contacted me and said that all of the inputs and outputs were above-average and there is absolutely nothing wrong with the amp. Maybe I need to change something else that I'm not thinking about. I'm not going to go buy thousand-dollar speaker cables but maybe I should change them. I'm using Audioquest Mackenzie interconnects to hook up my SA8005. I also have the Marantz TT-15 turntable and it's output is even worse. CDs don't necessarily come through weak, I guess I just I'm expecting more gain or presence, to use those terms.

The bottom line is that I feel like the weaker amp is stronger but there has to be a reason for this. I refuse to believe that this reference series Marantz product is out performed by a non reference series product of the same company. Because of all of this I'm considering selling the PM14-S1 and buying the Musical Fidelity M5si to see what happens. Everything I'm reading about Musical Fidelity products sounds fantastic and it seems that I would not be disappointed. But I've thought that before. If anyone has any experience with this stuff please let me know because I'm hesitant to get rid of this reference integrated if there is something else that I just simply need to tweak. If anyone knows about the difference in volume styles on my twoamps please explain those as well. Thank you for reading.