completely different types but I would go for a stretchie over a blueberry if I had to choose between the two.
I have a few issues with blueberrys (expensive, inserts wear quickly, bulky, aplix wears quickly, inner fleece wears quickly, not really suitable for overnight to name a few!!) but absolutely none with the stretchies.
As has been suggested if you want to figure out what you prefer keep an eye out for some second hand nappies in a variety of types so you can have a look at them and decide what you think you might get along better with and then when LO arrives find what suits him/her best.
My preferances for nappies changed dramatically from when I first started looking to now...
at first I didnt want "pretty" nappies and I wanted 2 parters (nappies that needed wraps) so I bought them. Then I bought a few other types just to have around (developed an addiction more like...) but when he arrived I found some just didnt work for us, my OH didnt like the poppers and kept forgetting to put wraps on so I sold a lot of my two part nappies. When I started out I also didnt like side snap (poppers at the side instead of the front) but now they are some of my favorite types. I am also now prefering two part nappies for bedtime, they work much better (I use the tots bots stretchies at night a lot).
I have also changed preferance in daytime nappies too, I almost only use three different types (Itti Bitti d'lish, Blueberrys and WeeNotions) and I use one type for going out (Flip Organics)
So it is probably best not to tie yourself to one nappy....HOWEVER if I had got the stretchies right from the start I would have kept on with them because of how they fit.