I am one that competes in both. I am on my first dog and the training group that I got involved with does FT, but I started in HT. I ran a few club derbies, just to support the club and run my dog, since I was there to help anyways. I got a SH on my dog, and started running Qualifying stakes in FT at the same time I was running Master stakes in HT. I ended up getting him QAA before I got the MH title on him.
It is doable. It is attainable. The two main differences between HT and FT.
1. Distance. HT is limited to 100 or 150 yards or less. FT is not limited. You can see 100 yards marks or shorter, and you can see 400 yard marks or longer.
2. Precision. While running blinds, I noticed that HT people line their dog up and send, no matter whether the dog is on a good line or not. FT people take the time to make sure their dog is lined up in a good direction before sending for a blind because initial line, length of carry of cast, and fewer casts count. As a result of this, I was able to 1 whistle many HT blinds at the Master level, because I took the time to make sure I had precision.
3. And of course, a HT uses a standard (that is subjective to the judges that weekend) and a FT is a competition. Only the best dog will win, and if you run in a series and do not have a chance to win, you get dropped. Only the strong survive.
Yes, as far as titles, and stuff, that is all in the rule book.
JH (junior hunter), SH (senior hunter), MH (master hunter). These are HT titles. As you go higher, the more requirements that exist.
FC (Field Champion) - Although not required, usually the Pro is running the dog. Need certain number of points and a win to attain title. Not easy.
AFC - Amateur Field Champion - Amateur runs dog. Need certain number of points and a win to attain title. Not Easy
Those are the only two titles in Field Trials (besides National being put in front of each of those titles, of which a National is held each year, and again, you need to get a certain number of points within the annual qualifying period to be able to attend and compete in the national).
Designation - Qualified All Age (QAA) - This is for a dog who enters the Qualifying stake and takes first or second place (they can also get this designation when competing and placing in AM or place or JAM in Open or something like that).
Non official AKC title - Derby Champion - This is for the dog who has accumulated the most points in the Derby stakes. The Derby is for dogs who are under 2 years of age.
I think that is a quick summary.
Good luck if you do decide to run both. It is fun, and all about spending quality time with your pet.