I can tell you that even my Nexus 7 is rather abysmal at handling Google Docs documents. The Bluetooth keyboard connection is flaky at best, gets much worse when Wi-Fi is turned on (which makes working on a cloud document rather inconvenient), the typing often lags far behind the keyboard, it's hard to do anything beyond the basics (e.g. I actually need footnotes to cite things in the work I'm doing), etc. etc.

I haven't used a Surface but from Mike K.'s description it certainly seems like it could better handle some of those tasks. Maybe Lollipop will help, but I won't be able to tell until the OTA loads.