Might want to watch out for performance claims, at least put them into perspective. Most guns are 'rated' for the
lightest pellet in each caliber, and Gamo's PBA (pot metal) pellets are a typical example. .22 Match shooters know that staying sub-sonic will escape projectile buffeting during the transition from supersonic (~1100fps) to sub-sonic. (1050fps is typical for 'match' loads)
All an airgunner has to do with the highest performing guns is to go up in pellet weight until max speed is around 1000fps or less. Not a prob with the Benji NPXL 1100 (supposed fps with 8g) as std .22 cal weights (~14g) are quite a bit slower than that. Penetration depends on velocity & profile (dia) so you want the best of both. btw those 'fast' PBAs can ricochet in a way that lead won't, so use with caution for anything but punching paper.
Energy calculation, if that matters, has been derived to a simple formula that transposes units. Velocity (whole thou's fps, so 1000 as 1.0) squared X 2.22 (a constant) X bullet weight in grains = ft/lbs energy. Example: 14g pellet at 800 fps. .8 squared X 2.22 X 14 = 19.89 ft/lbs. This applies to all calibers, airgun or firearm, but only to
muzzle energy that succumbs to wind and drops quickly according to a projectile's frontal area and weight. (basic ballistics)
One pro'ly should keep in mind that a first airgun need not be the 'end-all' and is only a starting point. (yes, addictive if you like to shoot economically

) Features mentioned above will be missed or appreciated as time goes by, and I'd bet I'm not the only one who learned what they liked and didn't like about their 'starter' airgun. For me, it was bye bye metal coil spring, and see ya .17 cal. YMMV, but one has to start somewhere and IMO that's ~$100 with all too many to choose from. Have fun shopping! tog