Which guard do you prefer (closed, open, rubber, butterfly, half) and how do you use it? By that I mean do you look for sweeps, or more submissions, or what.

Bodyguard, then I don't have to fight.

Awareness then you don't need a bodyguard.

I wish I knew what all those rubbery butterflies meant but I prefer what would probably be considered a very closed guard the only thing I really change in my guard is the width of my stance.

I meant more of the submission grappling guards actually.

Well sad to say I am not experienced there... Widening my stance is one of the responses to deal with takedowns.. Wish I could change that but nothing where I live

Youtube my friend, that is the answer. A wide stance helps but it goes far beyond that for guys get real deep or go for single leg takedowns. Then again where you are you may not need to worry about that anyway.

I have limited BJJ experience. Done a few classes with Gracie Barra and a Carslon Gracie Jr affiliate, but most of my BJJ has been in a Gracie Garage. We roll quite a bit, and recently my sparring partner and garage owner (who studied MMA for 4 years) has started adding gentle punches in to our rolling. That definitely changed my perspective on grappling!!

I've only played Butterfly guard a little bit. Didn't like it, I was too easy to hit (my sweeps aren't great though).

Not too keen on rubber guard either. Seems ok in theory, but it does require quite a bit of flexiblity. Some people have a better range of motion than others (even if everyone is stretching). It's a guard that is too attribute-specific to be well used IMO.

Generally I stay in closed guard. If nothing else it stops me getting hit better than any other guard you mentioned. I'm not terribly experienced in BJJ/Sub Wrestling/MMA though.

If we were just doing BJJ, I'd maybe play about with different guards. If we are rolling w/ punches, closed guard. Thing is though that I should really keep it consistant. I am trying to have the same game whether we are rolling w/ punches or not. If I go in to what I call "Sports BJJ mode" I might start doing things that would get me a slap in the chops in MMA sparring! As with anything in MMA, I use the acronym KISS:

Keep
It
Simple
Stupid!!

The 1 thing that gets me about youtube when you see BJJ challenges from other styles is that the Challenger looks like they're not even worthy of a Yellow belt let alone a Black Belt! The only time where I see some reality is on UFC

Then again, it depends on what rules they are "fighting to"!

The Guard needs to be natural, whatever one you take and it has to be adaptable against strikes from strikers and takedowns from grapplers.

If you've never done any grappling you will never know until it is too late how weak your guard is. the same for grapplers, they need to work on striking to know that they will have weak points in their guard that "authentic" strikers will find gaps in

My teacher had great BJJ experience but moving had put that on hold as well and we never got to much grappling.

As for ever needing to know or not that's kind of irrelevant the chances of being attacked by someone who is proficient in any kind of grappling anywhere in the world is pretty slim.. I just want to be a better martial artist and being able to grapple is a big big part of that I think the striking part I have down quite well and that's something I can maintain speed and power wise, even improve, on my own.