Are Monoblocks better than Multi-channeled amps??

Yes, BUT: That does not mean cheap mono blocks from company A are better than a we11 designed multi-channel amp from company B.

Or that dual monos in a single case aren't just as good as separate monos. Dual power supplies are a step up but still don't beat monos for channel separation or crosstalk which really is the point imo.

Good thing I used words like "typically" and "generally".

Also dual monos on a single chassis tend to get very heavy and large.

In general, monoblocks are better than multi-channel amps, mainly for 2 reasons:

1) Separate power supplies provide more instantaneous current to the output stage.

2) Because the L/R circuitry is housed in separate chassis, there is no interaction between the two (better separation and soundstaging)

Whether the added cost is worth it depends on your priorities, wallet and space.

bondmap,
I would agree a top level and high standard built stereo chassis would likely out perform a modest design and built monoblock amplifier.
However when companies offer both choices or go 'all out'their monoblock version is the upper tier amplifier with rare exceptions Same as when a product can be silver or copper(cables,amp wiring,transformer windings etc.), the silver version within a line is the upper level version.
Regards,