In the long run Metal Gear certainly outshined them, but I think the Syphon Filter games were ultimately very different.

One of my favorite little bits of goofy trivia between both series though was the joke in the dialog of MGS 3 : Subsistence where Snake asks the Colonel why “Sam” (presumably Sam Fisher of the Splinter Cell series) or “Gabe” (presumably Syphon Filter’s protagonist) couldn’t do the Ape Escape side mission instead since Snake said it wasn’t really his “thing.”