We recently bought a Max Tapener tying machine, and have just started using it in earnest for tomatoes and broad beans. It's fantastic - really fast and efficient. It uses a soft tape, and each tie takes only moments.
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It's £36 from Amazon.co.uk (using the A4A link, of course :) ), plus a few quid for refills of tape and staples. I realise that you can buy a lot of raffia for that price, but this gadget now lives in one of our trugs, so useful has it proved.