SSS provided plenty of replay value for my TurboExpress. I was never into the idea of a portable; the TE is the only one I ever bought cause of TTi's $99 sale (and maybe thinking I'd get the TV tuner eventually), but playing SSS once in a blue moon in bed with my TE was enjoyable...well, not as "enjoyable" as say
taking a shit in a porta-potty mind you, but yeah!
It's a solid, challenging shooter, especially if you enter the code to access the maximum difficulty, and a good deal of its awesomeness in my book stems from the music from stages 2 and 6.
I tried Soldier Blade a couple of years ago with Magic Engine, and I dunno, I didn't form any bond with it; I played it, beat it, and never thought about it again. I recall it was more colorful than SSS, but I don't think it had good music or anything that really stood out which makes a big difference. I own the CD of "Summer Carnival '93 - Nexzr Special" and I think a lot of the fondness of that game comes from the music.