Yes or No?

Too much clutter or actually useful? I won't be racing.
I'm on the hefty side, will they actually work?

And yes I know I should try them for myself.

When I bought my cx bike I left them on, found I never used them after a few months so took them off.

So you're right you should try them for yourself.

NOOOOOO

use flat bars if you can't cope with proper brakes!

They do actually work though

Yep, they're pretty good. If you're going down something seriously steep they allow you to shift your weight back a bit. Also if you're getting tired in the drops on rocky ground they're useful to provide an alternative position.

They're as powerful as your normal brakes.

There will be some people along shortly to slag them off, ignore them and give them a go.

use flat bars if you can't cope with proper brakes!

?? but its the same brakes, he's just got an extra set of levers. Why the 'nooooooo' thing?

The clue's in the name of them.
I've probably got a slightly skewed viewpoint being brought up on 'saftey levers' on 10 speed bikes with chrome rims.

I am neither for or against them. My son has them on his cross bike and I don't have them on mine. The only downside is they add more friction to the brake cables so alter the feel on the drops.

I have them on my cross bike. It allows me to have a longer/lower position at the hoods than I might otherwise have but still be able to get my weight back for steeper stuff.

But then I ride my cross bike on stuff that cross bikes aren't really designed for (eg twistier/steeper) and if I was actually racing cx then I'd have my bike set up so that the main hoods position was right so that I didn't have to move my hands around.

So depending on what/how/where you ride they may or may not be a good idea.

Nick Craig, 3 Peaks using bar top levers.
For Proper CX racing no. For everything else (inc leisure/commuting) yes. Means you can sit up on the tops along a canal towpath and not have to frantically reach for the levers when a dog runs out in front of you.

they came on mine and can be useful as people have mentioned for different riding positions & conditions, so they're staying there.

If I really need the space they may have to move, but no need yet.

I imagine that Nick Craig has them for the three peaks for the same reasons as me – there's plenty of road so he's got the bike set up lower for the road sections with the chicken levers there for the technical descents.