There are loads of good brand name heaters out there. In most cases price is somewhat proportinate to quality. Now if you one that will last almost a life time there are the titanium heaters. I know when they first came out they started around $150.00 and you needed a temp controler to run them. But these also come in higher wattages up to around 5,000 Watts. Personaly I'd be afraid of a super hot spot with a heater that big.
But on the other side if your spending $40.00 on a heater and replacing it every 5 years, a heater that last 20 years is worth $160.00.
Dennis