I had the Macintosh MA6900 integrated amp several years ago and, based on my retailers advice and demo, I finally purchased the Luxman L-590ax II. The Luxman amp was more detailed, more musical, clearer, warmer and I enjoyed it very much.
My next upgrade was to the SimAudio 700i V2 integrated amplifier and it took my musical listening to another level. I auditioned the 700i V2 amp and liked what I heard using my PMC Twenty5.26 speakers. My new SimAudio 700i V2 amp sounds excellent with clearer sounds and more musical detail.
If possible, audition different amplifiers at slightly different price ranges to narrow down the range you can afford and sounds the best (to you). Take your time and listen. When posting on Audiogon, you are getting opinions from others and that is useful. However, I suggest you audition the McIntosh amp and the Luxman amps and decide based on what YOU hear.
As posted above, I agree the Luxman L-L-509X is a great sounding amplifier and, as I noted, suggest you audition it so you can make the correct decision. Please do NOT rush this process.