99 has the Mid State marker,, a Redwood northbound and a Palm southbound,, Madera still has the B-17 along the side.
5 is more direct and I feel it is faster,, also you have In and Out in Kettleman City and the Tri Tip sandwich at Harris Ranch warrants a stop..
99 runs you through the center of allot of small cities,, 5 you are way on the out skirts.
The base of the Grape Vine has some nice eateries,, and a few places to get out and walk....
Fort Tejon is a good tour,, and if you get a chance,, Find the Old Ridge Highway!! 7 mile detour Packed with old history of travel over the mountains...
5= brain dead fast!!
99= scenery slow!!
both have rough spots,, but from Modesto to sac,,99 is a NASCAR run!!! Jack Tone road and north seems to be a speedway..I usually take the 4 over to the 5 and it seems wider,, Although Elk Grove into downtown is no place to lolly gag either..