Which is the best controller mode for gliders? I am a beginner and most guys in my club fly mode 1. I am a pilot myself and find mode 3 (pitch/roll on left stick and throttle/yaw on right stick) the most natural for me. However, will I find this a disadvantage if I move onto more complex glider in the future?

Can't specifically answer your question, but most fly mode II here in the U.S. Myself, I fly mode II for fixed wing and gliders (which is opposite of way you fly)... and I was a former full scale military pilot. As far as finding mode III a disadvantage when moving 'onto more complex glider' in the future, I wouldn't think so... assuming your RC equipment was programmable enough to meet your comfort level.

Doesn't matter.  Whatever is popular locally would be what I would recommend.  They all work.

In North America Mode 2 is the standard, so I have never tried any other.  But I don't see that it really matters.

If you can't find a set with mixes and other sailplane functions in your mode then you may need to look at getting some internal changes made to the transmitter to move the stick functions around.

Frankly I'd suggest you learn to convert over to one of the more standard mode setups. It's one thing to move the throttle ratchet over to the other side but often the channels assigned to the sticks are set and the preprogrammed mixes expect the stick axis' to be where they are supposed to be. In the old days most of the transmitters used sticks which were separate from the circuit boards and were wired. In such setups it was simple to move the wires around to put any channel on any stick and axis. IF you can find a transmitter that still uses this method instead of the ones I've seen where the sticks are soldered right to the boards you could do the same thing. But you will likely find that you are restricting yourself a lot as the need for new or more radio sets comes up. It is likely easier to re-train yourself now before it becomes too ingrained.

Mode only matters in two instances:

1) you want to teach someone else ( you know mode 3 and their equiment is mode 1 or 2)
2) you want to let someone else fly your plane (No good if they know mode 1 and you are set-up Mode 3)

Mode 3 is one of the less commonly used formats as far as I can tell. Seems mode 2 is most popular globally followed by Mode 1 outside North America. I have never seen a radio advertised in Mode 3, though some can be reconfigured to Mode 3.

Many of the more advanced sailplane radios offer a software setting for modes. You can select mode 1-4 from a menu. Look for this feature when you look for a new radio.

I am not sure, but I think these provide software Mode select,but you need to check before you buy..

Hitec Aurora 9
Airtronics SG10
Futaba 8FG
JR 9503
Multiplex EV0 9.

These are US names and may differ in your country.

Thank you all for your valuable input.  I can live with mode 2 which is just swapping the stick around.  It is like flying in right hand seat of an airplane.  One more question is that: why ppl fly mode 1?  I find it hard to separate pitch and roll into left and hand hand. 

What you learn first is what typically feels best. So if your teacher flew Mode 1, you will probably fly Mode 1. Again, I don't really think it matters all that much.

If the steering wheel of all cars were in the middle of the car, then that is what you would learn and that is what would feel natural. Having the wheel on the left or right in your car feels normal. Driving a car that has the wheel on the ohter side feels odd.

Ihave heard that Mode 1 may have some slight advantages for competition pilots, but if this is true, Iwould suspect it is marginal at best and probably falls back to flying what you know.

At least with Mode 2 you will likely find other pilots flying this mode as well. And you will likely have more choice of radios.

Whatever works for you.