Best is always difficult as its so subjective.
From my perspective the hotels along the bath road are all fine, and i pick based on price and loyalty program.
Being a Scot, I tend not to pay the premium to stay in the sofitel.
Dont bother with hoppa bus. The bath road hotels are easily accessible by london red bus whish is free along the bath road as far as harlington corner,£1.50 thereafter. Quite a saving each way on the hoppa!!