glaspmart, you will see in the specs that in Mono mode the power rating changes significantly, doubling into 4 Ohms (and again into 2 Ohms with amps that are more suitable to drive less efficient speakers and ones with difficult impedance curves). Doubles again to 400wpc in Mono, and that’s a big difference in output from 100wpc. Pay attention to the speakers you would pair with this amp, as 1. It’s not rated for 2 Ohm speakers, and Mono is only rated for 8 Ohm speakers. IOW, it’s not a workhorse, and could be strained to use in either of those situations. Most amps are well built enough to work in those conditions, but if pushed, could cause damage to itself and/or speakers. Respect the specs.
Doubling the Output makes easily perceived changes in listening; macrodyanmics are improved, bass seems more powerful and cleaner, but not necessarily more "plump"; more headroom, which makes the amp seem to be loafing/having an easier time of it; soundstage usually opens up more and seems larger/deeper, etc. Often there is a sense of more solidity to the images.
There is often also a perceptual decrease in absolute resolution, and for that reason, some prefer biamping. Some may feel the change imbalances the frequency spectrum, and so would opt for less power and what they consider more top to bottom coherence.
Every amp is a discrete experience, and while most amps from same manufacturer are fairly easily assessed (i.e. Usually a more robust, upper end stereo amp bests two lower end mono block units - Yes, I have tried that comparison several times), no one knows absolutely which would be better performing once amps of different build (i.e. stereo, mono, etc.) are compared from different manufacturers. Generally, the upper end brands are far superior, but one simply must compare to make any definitive statements - and then, it’s a matter of preference. But, usually far superior amps garnish a lot of fans.
You simply must compare all the amplifier modes if you want to get the best result that you enjoy the most. Do not simply take advice from others who have completely different systems and have different preferences as though it’s universally superior for your setup and preferences.
Any of these could be preferred:
Different amps
Upper end models
Stereo bi-amp/ Mono with bi-wiring
Different Integrated amp
or
The one(s) you own in various configurations
Bi-wire is simply running to different sets of cables out from the amp (either from one or two sets of output posts on amp) to two pair of speaker inputs. If you want to use only one set of speaker cables, then you use a "jumper" between the two sets of speaker input posts. As might be expcted, there is also a difference in sound when comparing these two methods, and even changing speaker cables or mixing them in doing so confers yet another change.
There are MANY options and results to explore. Or, you can set it up one way and forget it, but you will likely not have the best sound by ignoring all the options.
BTW, amps perform in seemingly radically different ways with various speakers. I have had products I thought I knew pretty well, having used them in many rigs with four or five speaker systems of different genres. Then, I paired it with a completely different genre of speaker, and... WOW, the performance leapfrogged that of amps of a different genre. Did the less costly amp typically do so, no, not at all- so do NOT expect budget amps to pull off things like that typically. It took a particular type/technology of speaker and building dozens of systems to do so. So, one in about 20 systems was a shocker. Will the average audiophile find that? Perhaps, if they want to build 20 systems. The idea that anyone who buys a budget amp is going to get that kind of result is nonsense. Because of reasons such as that, when people make declarative statements about what is universally best, they are often wrong.