Now, industry watchdog energywatch has put it all together to rate the best and worst in a simple format allowing easy comparison.
Paul Savage, energywatch business services manager, said: "Until now, small businesses have been starved of information to help them compare suppliers.
"Our league tables should empower consumers and spur suppliers on to improve their customer service. Companies languishing at the foot of the league tables have much to do and those enjoying top spots will want to retain their positions."
Of the "big six" energy companies, Scottish and Southern Energy (SSE) was rated top and British Gas Business (BGB) bottom.
energywatch found that BGB came last in every category it measured except for sales, where it came out top.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.