Leopard gecko, crested gecko, or red sided skink?

i have a 20 gallon long that will be empty once my bearded dragon gets its new enclosure. ill trun it so it's tall if i get the crested but i dont know which one to get. i like the leopard gecko bc so many people say they are great for handling, but i like the crested gecko bc it doesnt need insects, but i like the red sided skink bc it's rare and unique. so pretty much theyre all great but i want to know everybodys experiences.