Thanks, Punarvasu. I found compositions in Keeravani to alternate between being lighter and more emotional than Simhendramadhyamam which is a rather more grim and austere raga (with a tinge of deep emotion). I guess both ragas conjure a sense of nostalgia to some extent, although this is more pronounced in Simhendramadhyamam.
Really? I find Simhendramadhyamam kinda sensual (hope the filter does not chew and spit this out) while Keeravani more morose. This may be because, among other things, the former is sung more in the upper ranges while the latter's swaroopa resides more in the lower range.