g_nakamoto, my thoughts: You are a brave soul for asking "any comments on this" on a site such as this! Given your purchases of the 501 and, thereafter, the 901, I would hazard a guess that you like jazz and music with a solid midrange. Properly placed, those speakers certainly deliver in that department.
I bought my first quality audiophile system in 1972 on a poor student's limited budget. After spending most of it on a receiver (Sansui 2000X) and turntable (Philips 212) I settled on a pair of Studiocraft speakers (made by Bose in those days). The shop had a wonderful policy allowing full trade-in value on those speakers toward a purchased of more expensive ones if purchased in the next 365 days. A year later, I returned to that shop to upgrade the Studiocraft and spent several hours A/B'ing many pairs within my budget range. It was a large shop with a huge inventory (Tech Hi-Fi Cambridge, MA). Those were the good old days for audio shops. I A/B'd pair after pair and worked by the process of elimination. I very much enjoyed EPI, AR, Advent and others but eventually whittled down the competition to Bose 501 and Ohm C. I listened to those for a long time because I liked them both very much. Eventually, I chose the Ohm C largely because, to my ears, I thought they were a bit clearer, more dynamic and did a better job with acoustic instruments, especially acoustic guitar. Regardless, the 501 were very nice speakers, indeed. Just for fun because I certainly couldn't afford it at the time, the salesman had me A/B the 901 with the Ohm F to see what I thought. The amplifier used, as I recall, was either a McIntosh or Phase Linear. I didn't have to listen long. My ears definitely preferred to Ohm F largely for the same reasons. As you are probably already aware, speakers, more than any other components, are a very individual and subjective choice. Different ears like different sound(s).
I bought my first quality audiophile system in 1972 on a poor student's limited budget. After spending most of it on a receiver (Sansui 2000X) and turntable (Philips 212) I settled on a pair of Studiocraft speakers (made by Bose in those days). The shop had a wonderful policy allowing full trade-in value on those speakers toward a purchased of more expensive ones if purchased in the next 365 days. A year later, I returned to that shop to upgrade the Studiocraft and spent several hours A/B'ing many pairs within my budget range. It was a large shop with a huge inventory (Tech Hi-Fi Cambridge, MA). Those were the good old days for audio shops. I A/B'd pair after pair and worked by the process of elimination. I very much enjoyed EPI, AR, Advent and others but eventually whittled down the competition to Bose 501 and Ohm C. I listened to those for a long time because I liked them both very much. Eventually, I chose the Ohm C largely because, to my ears, I thought they were a bit clearer, more dynamic and did a better job with acoustic instruments, especially acoustic guitar. Regardless, the 501 were very nice speakers, indeed. Just for fun because I certainly couldn't afford it at the time, the salesman had me A/B the 901 with the Ohm F to see what I thought. The amplifier used, as I recall, was either a McIntosh or Phase Linear. I didn't have to listen long. My ears definitely preferred to Ohm F largely for the same reasons. As you are probably already aware, speakers, more than any other components, are a very individual and subjective choice. Different ears like different sound(s).