Given the choice for engines, I think I'd go for the SuperTigre. You're not going to get stellar performance out of either one , but it should hold you until you can get something better. The UCD really doesn't need high-dollar servos to run. Some standard Futaba 3004s will work just fine on the elevators and even ailerons. You may want something a little more powerful on the rudder. I just picked up a couple of GWS S03T (I think) servos that are rated at 100 oz. They're slow as molasses, but they were only $10 each. I figured for that price, I'd live wih the speed. So far, they've worked out fine. If you can afford it, a 5 cell battery pack will buy you some more speed and torque from the servos, too.

Good luck...