Well, either or, it's about being babyish and it's about nappies.
Never tried Bambinos. Would like too, just because I've heard so much about them.
Out of the brands I have used, I notice there are nappies that make me feel I am more baby-like (because the nappy is larger, less clinical looking and not leak-prone) and then there are other nappies that are built more like a modern baby nappy would be, but are less effective on an adult. The Boots StayDry brand seem to be an adult version of the Boots baby ones, although I haven't bought baby ones to compare. What I mean is, they use all SAP, no fluff, are cloth-feel, have strong elastic leg gathers such that the nappy cannot lay flat, have elastic on the front and back, and come up less far when wearing. They seem the most similar-to-baby-nappies, adult nappies I could buy, if that makes sense. But, if I wanted to look or feel more babyish, I would wear one of my Tender-Care Night Large, because they absorb a lot, are plain white (with blue tapes) and are big!
There are lots of great diapers out there. Since everyone is different (body wise) and has different needs I don't think there can be one "best" diaper. Personally I enjoy trying diapers I have never tried before. I don't have a "best" diaper that I tend to stick too, since I have different needs/desires/situations.
I've used Abenas and i've used Bambinos. I'd like to say that I prefer Bambinos more since they're much more aesthetically pleasing to me -- and really, isn't the babyish look about diapers kinda the point of them? It adds more fun and more enjoyment to my diaper time :3
I like Tranquility ATNs. They're thick, yet quite comfy to wear, and hold very well. They also have a subtle but pleasing "diaper" smell. OK, so they don't have fancy designs... but, eh, I just throw on print plastic pants or a diaper cover
I haven't had any Bambinos to compare Tranquility ATNs to yet (but will soon!)
They're really comfortable, with a very supple pure white plastic cover and a couple big broad wetness stripes that you can make turn blue
ATN stands for All-Through-the-Night, and in my experience, at least, they live up to the advertising. They have a good mix of fluff and gel, and they really, really lock away the wetness while swelling up nicely. Even when it's good and wet, you can lie down or sit down and squish all you want, you won't leak. They also have quite tall leakguards and a good seat bulge.
My main complaint is that the tapes are the "stick once or twice, then that's it" type - it takes a little getting used to, and it's a definite negative compared to the Secure Plus/Bambino-style "adjust a bazillion times" taping panel. The tapes are very reliable and not prone to popping off, but if you try to adjust them a bunch you'll end up tearing the plastic.