Surface Pro 3 vs. 4 - Advice

[poppydent]

I run a little business from home & I spend a lot of time standing around at sales so I am looking to get a hybrid laptop that I can use on the go. Can anyone give me some advice?

Has anyone got a Surface Pro 3 or 4... Is there really masses of difference between the two that a non-gaming person is going to notice? Would it be better to get a Surface Pro 3 with the Surface Pro 4 accessories? Or should I just spend the (huge amount of) money on the Surface Pro 4?

Any advice would be gratefully received... even if it is telling me another hybrid to look at.

PS... I don't want to go down the Apple route as we are an Android Family and I don't want to change everything.