I have a newly aquired set of three MG1.6, having returned to the Maggie fold after a few years in the wilderness. I have long used a center channel because my room layout would put stereo speakers too far apart, but the third speaker also permits them to play a bit louder without distress. Moneywise, even a set of three will set you back far less than any comparable pair of box speakers.
Based on experience I do believe that a high power amplifier is helpful, and you don't have to pay a lot for it. Maggies are a very easy (resistive) load for the amplifier. I use an Adcom 5503 which is good for 350 watts/channel at 4 ohms, and I use the MG1.6 crossed over from a subwoofer system at 90 Hz 24 dB/octive.
Why 90 Hz you say? Yes, I have verified that my MG1.6 are flat to 40 Hz, but I have gone up on the SW crossover frequency based on listening experience. Most everyone assumes that the SW crossover frequency ought to be based on the LF capability of the main speakers, but I have come to believe that the HF (if you call 90 Hz HF)capability of the subwoofer is an equally valid criteria. Although the MG1.6 do respond down to 40 Hz I think that they are working too hard at it, and the LF "flapping around" of the milar diaphram can only degrade the most important sonic performance in the 100 to 800 Hz range. You would need to evaluate the abilities of your particular subwoofer in deciding what to use for the X/O frequency.
In truth, except for a very small percentage of music the LF response of the MG1.6 is entirely satisfactory without any subwoofer. Furthermore the response that is there, down to 40 Hz, is very smooth, and gives the impression of going lower than it actually does. I found that room resonances that were clearly evident with box speakers, are virtually gone with the Maggies. One final point...don't even think about extending that LF response through electronic equalization. My observation is that any amount of boost below 40 Hz has absolutely no effect. When they quit, they quit.
The only criticism that I think is valid is the visual one. I have heard them called "ugly room dividers". Well, that's a matter on which we can all have an opinion, but I have never seen a box speaker that I consider beautiful.