depends on whether you want a gun that recoils, or recoil-free. & whether you want a lightweight gun, or something with more heft to it. the hw45 is all metal, heavy, spring-powered, & recoils. the alecto has a lot of plastic in its construction & is therefore lighter, is piston-powered, & doesn't recoil. as far as the calibre is concerned, the choice is yours, but i prefer .22 whenever the option is available.