As someone else said, short is a relative term.
At 5′ 9″ I keep getting told to size up and get a large bike but I simply don’t like how they position me compared to my usual medium.
I tried loads of these new breed of long bikes when I bought my Trance earlier this year and for me it was horrible….the long top tubes had me stretched out, coupled with fashionably wide bars I was then splayed out too….the end result was me effectively unable to move on the bike, stretched out in the middle of the thing in a precarious position for descending….it felt like I was on my road bike, far too much over the front….when I’m descending I like to be able to get my arse down and back , on extreme stuff that may mean nearly scraping the rear tyre with my bum….and this new school geometry didn’t allow me to do that, it effectively had me locked in the centre of the bike…..i felt like a passenger, a sack of spuds on the bike….I can see why people have OTB moments riding like that!…. It’s not for me, I’ll stick with mediums (or even small sizes, my 456 was 16 inches) and enjoy being able to move around on the bike instead.
Some sage advice I had from a bike company no less was that it’s easier to size up a small frame and make it fit with longer stem, lay back seatpost etc than to be stuck with a frame that’s too large, you can’t exactly hack away at the tubing if you’ve bought too big!
Obviously you want a perfectly fitting bike but if you’re between sizes like I often am I reckon it’s a safer bet to go smaller but each to their own.