TXU is high because they charge their customers for the "fuel" to run their power plants - that's what the supervisor told us when we called to complain about my godmother's bill. Her actual usuage was $350 and they charged her an additional $350. And she didn't understand the bill so she had been paying it for months until we started looking at it. They are a rip off. Would never recommend them.
On the other hand, month-to-month variable rate (no-contract) plans don’t have cancellation fees. You won’t be penalized if you find a better deal elsewhere and want to make another switch. And, you won’t be stuck paying more than you should be if the market rate for electricity trends down. But, if it goes up, you’ll be paying more than your in-contract neighbors, and you’ll likely want to shop around again for a better deal.