I generally use in-text on pages that perform poorly for Adsense. On the few pages that I use in-text in tandem with Adsense, it's because I find that they provide a broader range of links for my readers than what Adsense provides - Adsense doesn't always get the targeting correct.
Actually, this has been working very well for me, providing a tidy side income stream. However, for whatever reason, the in-text ad network I'm using has started to pay really poorly over the past 2 months. I don't think it's the in-text nature that's to be blamed - because I'm still registering a fairly reasonable amount of clicks every day. This tells me that visitors ARE finding the links helpful. However due to the very poor per-click value I'm getting now, I'm planning on plugging out the code as soon as I hit the next payment threshold.
I still think that if anybody can make in-text work, it's Google.