The deal with hurdle and combat jumping is that hurdle affects your jumping momentum. Rather than lose forward momentum in the air, it seems to give you the ability to gain some momentum while in the air, and also increases your jump height slightly to keep you in the air longer. Since combat jumping gives you excellent air control, and adds even more to your jump height, it combines very well with hurdle. Hurdle lifts the momentum restriction while combat jumping gives you the control to reach the higher momentum cap. This makes CJ and hurdle VERY fast. Not as fast as superspeed, but not too much slower than SJ.
As for the safety of teleport: Lagging isn't as big an issue since they fixed the problem where you kept your momentum after porting. It used to be that if you started falling before activating teleport, you'd be falling at the same speed afterwards. I'd say that the largest hazard with teleporting now is in landing. Usually, a spot that you choose to teleport is far enough away that the mobs there either haven't spawned or aren't visible, so there's very often a danger into teleporting into a group of mobs. Superjump sometimes has this problem as well, though if you're fast, you have a little time to react with SJ, and you also don't need to pause where you land, and can be well into your next jump before the mobs fire at you, so even if you get mezzed, you'll be safely away from them. I've only used teleport on my illusion controller, so invisibility prevented any TP-related deaths, but it's certainly NOT the safest travel power.
Fly gives you the option to travel in complete safety, if you're willing to go slower. Also, while fly and TP are equally good for getting around difficult areas (perhaps fly lags behind TP as far as speed goes), fly is MUCH better than TP for indoor mission maps, particularly the Oranbega tileset. Also, there's a lot to be said for not having to stay on the ground when a horde of mobs wants to pound on you with melee attacks.
I usually prefer to have both SS and fly. SS is cheap (effectively no prerequisite, doesn't take an extra pool) and fairly fast for long distance travel, and fly gives the greatest advantage in battle and the best mobility, and for long range travel, it lets me get over obstacles that SS would have trouble with. If fly were faster, all other travel powers would be fairly obsolete.
