I haven't got to see the Surface Pro yet but we do have the Acer W510 and the Lenevo Tablet 2 and I found the Acer wanting. It's specs aren't that different to the Lenevo (and need to remember both these tablets are way lower spec than the Surface Pro when talking about performance/price) but it always seemed to be slower, nothing ever felt quick about it.
We had problems with the touchpad on the W510 keyboard as well (had lag and sometimes didn't respond) but we received a recall notice last week for the keyboard, so at least that problem will be fixed.
I did notice the Acer does have a nicer feel to it than the Lenovo.
Between the Acer and the Lenovo I would take the Lenovo. Between the Lenovo and Surface Pro....probably the Pro but need to use one first. Also would want to try the Acer W700 before buying a tablet for myself, for personal use.
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