Stainless steel tools are worth the extra. Often my local garden centre.....wyevale.....has offers for high quality tools with lomg warranties.
I would suggest you look at what your local hardware stores or garden centres are offering and look for good balance, lemgth of handle, strength of blade, what sort of handle, length of warranty (many do carry a 5 or 10 year guarantee) and decide if it is relatively lightweight. The brand is not so important I think.
Stainless steel spades cut through the soil so much easier too and tend not to hold on to soil you want to turn.
When choosing stainless steel though check for strength....viz. that they don't bend too easily. I bought what I thought was a brilliant stainless steel spade only to find it would bend under any stress.....I am a little heavy handed!