Instruct: Classify Amazon reviews into positive or negative sentiment
Query: the 4500 is good, but get the 5000

I've owned the 2-speed 4500 for over a year and love it. I use it daily. But, I got to use a mutli-speed 5000 this weekend, and there was a huge difference. When I bought mine, I was under the impression that the high-end speed/power on the 2 models was the same. That was definitely not the case. The 5000 was far more powerful and absolutely crushed my smoothies. With my 4500, I have to be a bit careful not to strain the motor.