well, both are quite hardy and make nice pets. Me, i keep a leopard. They stay small (like 10 inches or so) but eat insects. Some are said to lick fruit juices, but mine seems to stick to his cricks. Both are desert species. Both can be handled fairly well, but i'd say you'd need to be a little gentle with leopards, them being small, thin skinned and all (especialy NEVER EVER pull the tail, its their fat reserves). Beardies are nice, but are kinda bigger and of course need bigger enclosures. How many do you plan to keep? A rule is one male to several females (both species are agressive towards other males, "in general"
. Both are good breeders. Both are often bred and both prolific breeders, meaning both CB's can be found regularly in pet shops
Leopard:
Pro : small, handable, very pretty (with albinos and other colour mutations within reasonable prices)
Con : no rough handling!!! (actualy this applies for both, but beardies are larger built, and can survive sloppy handlings), mostly insectivourous (some people have problems with this, the smell of crickets, gut loading, etc)
Beardies :
Pro : not very picky, some canned food even available (certain occasions/when fresh food is absent), hardier when handled, some colour mutations available, like sandfire dragons, but these are still kinda pricey
Con : need bigger enclosures, if they bite, they bite quite HARD (considering either being bitten by a leo/a beardie, i'd choose a small harmless leo anyday, also since my leo never ever bit me)
This is in general, coz every animal has his/her own individual needs. Another species that i like are Blueys (Blue tongued lizards), but they are still pricey, especialy CB's, which are usualy the Aussie species (Aussie bans ALL of its native fauna 4 exportation). Omnivorous, nice disposition, and gives birth instead of laying eggs like the other 2 candidates above. Likes burrowing, bout 20 inches, depending on species (and individuals).
Good Luck with your choice
-----
My "babies" :
1.0.1 Indo BTS (Tiliqua gigas gigas)
1.0.2 RES (Trachemys scripta elegans)
0.0.1 Amboina box turtles (Cuora amboinensis)
1.0.0 Chinese softshell (Trionyx sinensis)
1.0.0 Asian leaf turtle (Cyclemys dentata)
1.0.0 Leopard gecko (Eublepharis macularius)
1.0.1 Indonesian Whites Tree Frogs (Litoria caerulea)
And hopefuly still growing...