The Fleshlight arrives in a discrete packaging. The prossie arrives if you're lucky.
The Fleshlight gives a first class blow-job (with some handy help). The prossie might let you stick your cock in her mouth.
You pay once for the Fleshlight, and easy to clean. You pay the prossie multiple times, even if it cleans itself (sometimes)
The Fleshlight can be hidden discretely in a bottom drawer/ The prossie needs a punting phone which has to be hidden in the bottom drawer.
The Fleshlight makes a sucking sound while you use it. The prossie makes irrelevant noises unless used for oral.
The Fleshlight will see you at any hour, 24/7. The prossie will see you if she doesn't have an excuse (see separate thread, prossie excuses).
The Fleshlight doesn't care about your skin colour, age, or whether you wear a condom. The prossie might (see page 3 of her profile, para 64) or might say she doesn't.
The Fleshlight doesn't stop to answer the phone. The prossie owns her phone.
Yet in spite of this, 1 in 20 prossies actually gives you a fantastic time that Fleshlights cannot simulate.