I dont know anything about the Titan, but, if Andy says it is just a rehashed BH at twice the price of an Ace 250, that's good enough for me. That would make the purchase decision easy - NO. Without going into it, I don't want a BH. The fact that it comes from K-CO, only makes it worse (IMHO). I simply won't deal with them.
I think detectors made by the "Big 4" are currently the only way to go for the most of us. But, I seem to benchmark all of the ones I come into contact with more and more against the little Ace 250.
Is it the best on the market? No. In fact, it can be a little hard to cope with at first - it's sort of noisy and quirky, especially in a trashy environment.
But, you might have guessed where I'm about to go:
For $200, I dont think it can be beat, new or used. It's depth capacity and the option of notch DISC that actually works is worth the price alone. Not to mention it's sensitivity to small objects and it's light weight and its ease of use and it's resale value should you NOT take to it and it's...well, you get the idea.
This time I recommend you succumb to the hype, get one and learn to use it. You'll like it.