Pros: They are great for dumping cold and hot break material. They are great for collecting yeast.
Cons: Unless you have temperature control on them, such as a fridge you can put them in, or a basement that is at a constant fermenting temp they will be somewhat useless. I have two morebeer 12 gallon conical fermenters, but I have a big Trauslen two door fridge to stick them in.
Conclusion: It's a luxury item that only benefits those with temperature control. There are other inexpensive and practical fermenters, such as carboys or other 15 gal stainless steel kegs that can be converted into fermenters.