To me, the most prominent characteristic of the the 1SC's was their smooth midrange. The Aleph 3 sounded liquid and open through them. A great match. The highs were also well laid out, prominent without excess emphasis or graininess. The well-behaved character of the Aleph in the highs was important viz the relatively revealing treble of the 1SC's. The bass was OK down to the midbass, but of course needed a subwoofer. I've heard the Aleph amps criticized by some for soft bass. Naturally, I couldn't tell with the 1SC's because they rolled off before the low bass.
In contrast, the R1's seemed to be weak in the midrange. I think there is a slight trough in the response. I attributed this to the speaker more than to the amp since I had just swapped out the 1SC's which were fine here. The highs were great, with a sweet, feathery lightness that reflects the R1's ribbon tweeter. Again, the Aleph 3 was beyond any criticism in the highs. The R1's pretty clearly went deeper in the bass than the 1SC's, although not to the lowest octaves. I still have the subwoofer in, although set to a lower crossover. I have said before that I think the R1's woofer has been stretched to the low end and that's why there's a little gap in the midrange. The R1's with the Aleph 3 didn't produce the tightest bass, although certainly not flabby and definitely tuneful. (For example, my WATT/Puppy 6's driven by Pass X600's in another system are clearly tighter.)
Imaging and soundstaging were great with either speaker. I feel the R1's are better in dynamic range, especially at the frequency extremes, when both speakers are compared at moderately loud volumes. (I'm sourcing a Mark Levinson 390s directly into the Aleph 3, and all my cabling is Cardas Golden Cross.)
Both speakers are good examples of the minimonitor's art. However, they do sound significantly different. Of course, I recommend auditioning them to assess their suitability for your own taste.