Maybe I've been lucky but I have had great results with managed chat from a particular provider. The key was that I had a very proactive account rep and I closely monitored chat transcripts and offered my feedback to her team. We would talk a few times a month and developed a great working relationship. Their reps wouldn't just go for the info, they were given the freedom to answer questions they had the answer to or had been told how to answer. For example, if someone asked if a car was available their default answer with us was, "Yes, it is available. Did you want to test drive it today?" If someone wanted to test drive, their info was collected and we could always call them right back and tell them if the car wasn't available. Just because it's managed doesn't mean you can set it and forget it. Just like any other relationship with a vendor, you need to inspect what you expect and give them direction.
On the other side of the coin, I absolutely hate in-house chat because it's way too time consuming. When a user engages in chat they expect immediate responses, that's why they're using the tool vs a traditional form. So as the chat representative I have to give it my full attention, no multitasking (I've tried talking to someone on the phone while chatting and it never works out well.) The problem is that often times we don't have their full attention because they're multitasking. It may take 5-10 minutes for me to see a response from the user so I'm stuck.
Now if I take that same prospect and they engage in texting instead of chatting, they don't necessarily have that expectation of immediate response and a BDC rep can go about doing other things.
Long story short (too late), give me managed chat or texting. I don't think I need both and I certainly don't ever want in-house chat. Just my $.02