I have the LX521, which was the pinnacle of Siegrfried Linkwitz's (RIP) loudspeaker design prowess.
However, someone I know has the LX-mini (shown above, with the optional subwoofer, designated the LX-mini +2), and we did a shootout between the my LX521 and his LX-mini (without sub). The result was remarkably close in terms of ability to give a wholly believable phantom image. The only difference was bass extension, and the various LX-mini versions (with either closed box or open baffle subs) sort that problem out.
I have felt no need to upgrade the speakers for the five years I have been listening to them.