Start with size, because it sets everything else
The three names on your list describe rabbits of quite different scales, and scale decides housing and cost. The Dutch is a compact rabbit, usually around four to five and a half pounds, small enough for modest indoor pens and for confident handling by older children. The standard Rex is a mid-to-large rabbit, commonly in the region of seven and a half to ten and a half pounds, needing a bigger pen, sturdier arms and more hay going in and litter coming out. Lop is not one size at all: it describes ear carriage across several breeds, from the Holland Lop at roughly three to four pounds up to the French Lop, which can exceed ten pounds and is effectively a small dog of a rabbit. Measure your space against the adult size of the actual breed in front of you.
Coats: wash-and-wear Dutch, velvet Rex, varied lops
The Dutch rabbit's short, dense coat is the low-maintenance option, needing little more than a brush through during moults. The Rex is the opposite trade: its extraordinary velvet coat comes from a genetic quirk that also shortens the guard hairs, and the same coat sits over feet with less protective fur than other breeds. Rex rabbits are prone to sore hocks on hard or abrasive flooring, so a Rex house rabbit needs soft surfaces, rugs and fleece over any pen floor, plus a standing habit of checking the soles of the feet. Lop coats vary by breed, from the Holland Lop's medium coat to longer, denser coats on some lop types that mat readily and need regular grooming built into the week.
The lop ear question
Ears are the difference that asks the most of a lop keeper day to day. Upright ears, like the Dutch and Rex carry, ventilate themselves and are easy to glance over. A lop's folded ear restricts airflow into the ear canal, which means lop rabbits benefit from regular, gentle ear checks and a keeper who knows what a clean ear looks like, so changes get caught early. Some lop breeds also have broader, flatter faces than the Dutch's neat head, and in rabbits, face shape connects to dental comfort, so ask a breeder or rescue honestly about a particular line's teeth and choose a vet who will check molars properly at health visits. None of this rules lops out; it simply means the adorable fold comes with a standing maintenance task the upright-eared breeds do not impose.
Temperament and handling, honestly
Breed tendencies are real but soft. Dutch rabbits have a reputation for being bright, busy and a little opinionated, suiting a household that wants an interactive rabbit and can give it things to do. Rex rabbits are widely described as among the calmer, more handleable breeds, though any individual can break the pattern. Lops are frequently marketed as uniformly placid, and many are, but a French Lop's calm comes in a very large body and a Holland Lop can be spirited; temperament is shaped as much by breeding, early handling and neutering as by ear position. Meet the individual rabbit, handle it, and ask the rescue or breeder about its actual personality rather than buying the breed brochure.
Choosing for a decade, not for a photograph
All three types share the same foundations: eight to twelve years of hay-based feeding, space to exercise, a bonded companion where possible, neutering, and a rabbit-savvy vet, so the choice is really about which special needs you are happiest to own, the Rex's feet and flooring, the lop's ears and grooming, the Dutch's energy and opinions. Size decides the pen, the budget and whether children can lift the rabbit safely, and those logistics outlast the novelty of any markings. Whichever breed comes home, its particular needs deserve writing down rather than living in one person's head. KinsLe's Transferrable Profiles keep those breed care notes, vet history and routines attached to the rabbit, so if it ever changes home, the new keeper inherits the knowledge as well as the rabbit.