The simple way to think about them is-
End gathered. Traditional style hammocks and normally fairly cheap (or affordable) that are fairly comfy. I say fairly because they make
good day to day hammocks but 'some' users can suffer something called knee lock over night. Its where the stress between your ankles and your, erm, bum
is not supported sleeping, your spine curves outwards to follow the sag of the hammock, your knee's dont.
Side sleeping can get around this, but if you naturally lie on your back (as I do) it can wake you up during the night (the dull ache on your knee's)
To solve this problem, asymmetrical lay was developed in mid price hammocks (more fabric, more cost).
You sleep with your head to one side, legs the other. If the hammocks going 90 deg's, you sleep roughly 75 deg's across it (not along).
Then something called a footbox was developed to make the lay even more flat. This is a drop down section of fabric, specifically cut into the hammock.
The more upper price hammocks have this foorbox, a static ridgeline which keeps the same ammount of sag in the hammock (so you always get the same lay)
and a few other things like amsteel suspension- incredibly strong, non stretching rope. If you dont pre-stretch cheaper cord/rope (sit in for 20 mins after tying) you can,
as I have, wake up on the floor due to slow and progressive stretch in your cords. Amsteel eliminates the need to pre-stretch.
Bridge hammocks are like lying on a stretcher, with support poles top and bottom. you get a very flat lay. As simple as that.
You cant go wrong with DD or TW. The hornet was my first hammock and served me well for about two years. It will do you no harm to have a look on hammock forums
if you decide hammocking is or you. A great out and about hammock can be made with something as simple as pertex, two steel rings and some amsteel.
Most of all, enjoy your hammock