sutapanaki you take a good stance toward your question! no answer is easy, which is why you ask here!
yes you are right, GBW will be very high with common gate - the gate is held strongly at a potential, it is AC ground. this guy only acts like a resistor, to instantly (or very fast) pass potential to the other side.
But the trade is this - you have to dump so much current into this, it can't be used in sensitive areas. Think how you would disrupt the delicate 1/2-1/2 balance of a diff amp if you add a power-hungy resistor to the output side!
We know CMOS source follower uses capacitance to modulate the channel, so why worry about a little? 15fF can be driven VERY strongly by many signals, so our miller cap only hurts our input if we make the gain large enough to have a VERY strong signal on the output! Plus 15fF still means 2GHz from sub-micron CMOS..
You don't seem to need much gain (although 10-100x is always nice) so make a gentle souce follower if you are taking a precision output and moving it to another stage.
If your input is a power RF stage or something strong and very hi-frequency, 15fF will matter a lot. But to trade, you have a lot of power to give. Common gate is now best. You waste a little power in this "resistor", but you have a nice 1:1 buffer for your bipolar or GaAs output amp..
What application are you working on? Those necessities will tell you when to use each case.