I've been keeping and breeding lace monitors for quite a number of years. Although they can get very calm (I don't like using the term 'tame') they are a liability when in feeding mode. My breeding pair are incredibly calm animals, but the longer I have them the more I realise that I am always only one stupid mistake away from permanent injury. They are fantastic animals - my favourite captive reptile ever - and are full of personality, but if you're thinking beardie level handle-ability they are not something you'd want. My adult pair are calmly wandering around my feet as I type this (I'm wearing boots, not thongs), but if I had food smells on my hand and dangled it down beside me I'd be in serious trouble.
Spencer's monitors are more inclined to tail whip than bite defensively and would probably be the better option but keep in mind that most monitors do not enjoy being handled and after a few seconds of being held will usually squirm like toddlers wanting to get back down to ground level to use their own legs. If you're hoping for something that will sit on your lap while you watch TV, a bearded dragon is a better option than any monitor.
The other thing to keep in mind is that even relatively calm monitors don't start off that way and may take a very long time and a lot of patience to get there. Most monitors are shy as babies (lace monitors extremely so) and it is best not to handle them until they are older and bolder. Any force handling as you would do with a snake will tend to make the monitor crankier, more frightened of you and more defensive. One of the biggest mistakes people make when going from snakes to monitors is to assume loads of handling will quieten them down and then wonder why the monitor is refusing food, hiding all of the time and regurgitating what little it does have in its stomach when handled.
Here's my adult pair, being calm
[video=youtube;PxeB8kYPP0A]http://www.youtube.com/watch?v=PxeB8kYPP0A[/video]
Here they are, eating
[video=youtube;IYea2DgmVy4]http://www.youtube.com/watch?v=IYea2DgmVy4[/video]
[video=youtube;7NIOeF2ICmo]http://www.youtube.com/watch?v=7NIOeF2ICmo[/video]
Here's a baby bells showing why you don't disturb baby lacies. The pair in the previous videos used to be just like this, too.
[video=youtube;gAduW7A0lsU]http://www.youtube.com/watch?v=gAduW7A0lsU[/video]