Ask HN: Website live chat- worth it, and who to use?

I'm looking at adding live chat/support to the Pwinty website, as a way of engaging customers and answering their questions quickly.

So firstly- has anyone got data on how this has impacted conversion rates for them? Our target market is developers, so do you find live chat annoying or helpful?

Secondly- there seem to be hundreds of companies offering this service- can anyone recommend a supplier (preferably free, but I will pay for the right service).