The issue that I found with the IMS 'The Single' is one has to dose it beyond 'single' quantities for best results. For example, I found that I need at least 8.5g in 'The Single' for it to work. The big advantage is no grind adjustments are needed for double the coffee, i.e., I can use a 17g dose in an IMS precision basket at the same grinder settiing. As an aside, I did have to go with a Reg Barber C-Flat base with 'The Single' to avoid channeling at an 8.5g dose - with a flat tamper I had to go to at least 10g.
I also have the IMS clone of the LM single basket that Tidaka sells. With that basket (and Tidaka funnel and tamper) I can dose as low as 6.5g, although I usually dose 7.5g so I can keep the same grind setting as a VST 15g basket (dosed 15g).
I would say that I have found that the LM-style does more closely mimic the taste that a double basket produces. 'The Single' does have a unique taste. Perhaps ChrisCoffee summed it up best in their comparison video when they said that 'The Single' produces "lower acidity and a nice roundness" when compared to a conventional (non-VST) double basket.
That being said, I rarely pull singles with either basket. By far my best single basket is the 7g Elektra single, pulled in an Elektra Micro Casa a Leva