The "guts" of those two reels are in no way similar. The 4/0 Senator (the Red or Black versions) are built for much heavier usage. The jigmaster is fine for most purposes, but it will eventually fail if pushed beyond its limits. It's not a tuna reel or a reel to pull heavy loads in deep water.
If you go with the 4/0 Senator I would recommend you look at the Penn Baja Special. It's an awesome reel for what you are seeking to do. But it isn't cheap, about $250.00. It will last forever.
