What features are important in a hand mixer?
What I look for in a good mixer are:


A comfortable grip (I'm sure we've all have painful wrists after whisking up eggs whites or similar)
Well made, sturdy parts. (some whisks are strong others are just thin wire.)
Variable speed control
The Watt rating.


To answer your No.2 question, watts are important. They measure how much power the machine uses. Higher watts will mean the machine does more of the work and your wrist does less of the work. The cheapest machines on the market are only good for whipping light foods like cream and mayonnaise. If you plan on mixing up heavy fruit cakes or bread doughs, you should choose a higher wattage machine.

Paying for a good quality machine, if you can afford it, will save you money in the end. My mother has had the same hand mixer for over 35 years. She paid for a good one and it lasted. I however, like you, opted for a low price machine because I was on a budget, I am now on my third and this time I bought a sturdier model and I am much more satisfied with it. If I'd bought the better machine at first, I'd have saved myself £50 or so over the time.