Pretty much the same as Martyn.
I prefer the full fat version as it has a small screen which provides excellent feedback to the customer so they know when to insert the card, asterisks appear as they key in their PIN, tells them to remove the card and most importantly I can tell at a glance if it needs charging.
My wife on the other hand has several times left her PayPal card readers on by mistake and found that they were dead when came time for the customer to pay.
I imagine the Lite IZettle will be similar to the PP reader in functionality.
The iZettle price started out at an introductory £49, doubled and is now back to £49.
It's an expense but worth it in my opinion.
I don't know how much upselling you plan to do but having a card machine is useful when you've got a customer in front of you who has decided to go with that antivirus you just recommended or is holding the flash drive he now understands would be a very good thing to have to back up his photos but only showed up with the exact amount of cash needed to pay for the repair.