Of those two....give me the Fender. The Thumb is a fine bass, but it has an innate, midrangey tone that can't be EQ'd out. While that tone may be great for some things, I don't find it suitable for a variety of styles IMO/IME. The MM Jazz, or any good Jazz, is going to be more versatile and suited to a wider range of genres. Its one of the reasons Jazz basses are so popular, they just about everything and do it well...again IMO/IME.
However, one thing a Jazz will never do is sound like a Thumb, so if you're in love with THAT tone, you'd only get it from the Warwick. I recommend the Jazz, but really its down to whichever sound you're after.