Good question. I just happen to own both of these bikes.....
For starters, the 29 is a bigger bike so if you are 6'+ then it'll fit you a bit better. Suspension on the 29 is better with a fastace rear shock and fastace copy forks which use the same air/oil internal design as an Xrosin but seem to work about 25% as well as the genuine Xrosin's do???? Don't know why they have so much stiction??? The 29 is a much heavier bike and has a Ducar engine. Wether or not this worries you is all up to you.
The Pitpro 125 rear shock is crap and mine leaks after around 4 rides during which I did'nt pouund on it. The standard setup of the forks is equally crap and a 20kg kid would be able to bottom them out with no real compression or rebound dampening effect from the stock oil. The bike is overall lighter and uses a crf type `c` style frame. Lifan engine as standard but still not start in any gear. Swingarm on this bike is poorly chromed steel and weighs a ton.
Despite the -ves and +ves of both bikes, I like mine both. The 29 does dirt duty, and the Pitpro sees motard only action (once I relaced the wheels, replaced the swingarm, rebuilt the forks......blah blah blah).
Just remember that both of these things are chinese and need regular maintance. They are not the quality of jap bikes, but having said that, I'll never buy a crf50 and mod it as its just too much coin tied up in a toy.