I've vote for #1 or #3. Tahoes/Yukons tend to be quite reliable, and if anything does go wrong, most problems are easy to fix.
The Grand Cherokee doesn't have quite as good of a reputation. However my dad has owned a '94 and '98, both of which had the I-6 and over 100k miles. The '94 had a badly cracked exhaust manifold (apparently a common problem) and the '98 had a bad alternator, but otherwise both were very reliable.
