well, i've never played Spriggan, but i just purchased Mad Stalker and i'd say i'm a definite fan.
It is true however, the cinemas ain't worth a wooden nickel and 2 squirts of piss.
the load times are also very long.
otherwise i love this game. the graphics are great, the characters are large and move without flicker or slowdown.
the sound is average.
I think the game play is the strong point of Mad Stalker.
it plays like a very responsive, vs. fighting game except it's a side scrolling beat 'em up.
You can select one of 3 different mechs, each with it's own special moves.
you can also select the difficulty level and it's is fairly challenging on normal.
there is also a VS mode for 1 or 2 players where you can choose from 6 different mechs.
my only gripe is that the special moves are too easy to execute and they make it so you don't need to rely your normal punches and kicks as much as i think you should.
like i said, i haven't played Spriggan, but there are tons of shooters on the PCE and if you already have a bunch, i'd recommend MS.