I would suggest you try before you buy.
The first one I bought years ago was a cheapy A4 size. I did not like the
large size, it was cumbersome on my desk and I did not like the long distances
the pen traveled. I know this all sounds a bit strange, but when I purchased
the A6 size Wacom I use now, it just felt perfect from the start and I've
been using it a few years and never had a problem.