Joe - I started out with trannie film for six months, loving the colours and look after digital. V500 did a grand job while I was learning. I now prefer the more muted/subtle colours and contrast, and much extended dynamic range of neg film. Slide film, especially 400asa, can have very 'coloured' and blocked up shadows, when scanned with a flatbed. It's a great 'look', but it can get a bit much after a while. Neg is very forgiving on shadows and highlights, and I've found white balance very easy to get, 90% of the time on auto settings. Fuji Pro400H has been fantastic for me.
I doubt if there's much between differing flatbeds, you'd probably need to get to low-end drum scans to get the most out of slide film.