It's an expensive decision to make, to change brands. I had some small ittibittis when he was little, maybe I'll should try them again. It's a shame you can't hire nappies before committing to buying a whole stash.
you can hire nappies actually - over the years my child was in MCN, every so often, i would hear of a nappy website doing just that, hiring out for a fee, a selection of nappies (different styles, different brands) to people, from a "nappy library". I wish i could remember who did it, but i can't.

Also, another way is to experiment, by buying a selection of the various different types, BEFORE buying a large quantity of any one type/brand in particular. Some sites like Nurture Nappies used to do "mixed packages", many brands offer "trial packs" and you can always go to one site that has a flat postage rate e.g the wee wuns and buy one of many different brands/types = try them out on your bub, and THEN decide what you want to buy up on.