u can try TAE buffer that is good one..but the buffering capacity is less compare to TBE..so u have to change the buffer frequently..i feel some problem in ur apparatus..smearing may also be due to bad quality DNA sample..see your marker it does not have any smear..try to use TAE with 45-50 V and if still the center wells move slower than end ones change the apparatus and try again..hope u will succeed...
If your problem is uneven migraton between the middle lane and the lanes on the side, there are 2 possible causes/solutions.
1. Curved electrode (on either side)--> solution: change the running chamber...look for stright one.
2. Uneven polymerization of the gel --> solution: melt the gel well, pour while it's still hot like ca. 2-3 min after melting (make sure you use good quality tray though...otherwise it may crack), and pour in quick, single movement fashion (pour all at once, and make it quick). With this trick, my gels always stright like a ruler ^ ^