How are you doing your C25k? I dont really know which one I should chose!!

I do the timed version. I'm not worried about distance so much as endurance. When my endurance is built up I'll worry about distance.

For me knowing that I'm done in 25-30 minutes is a huge motivator. I like countdowns... they keep me focused.

Timed. Definitely timed!

I went for timed, think its easier to hit as a beginner :-)

I'm going for timed as well. I don't have a treadmill, so all my running takes place outdoors. It's hard to track distances right now. Which brings me to another question; treadmill or outside? Is there really a difference?

If you read my intro post, you'll see that I trained for 9 weeks on a treadmill. When I eventually ran outside, I felt like I had never run a day in my life! The effort it takes to run outside is completely different than running on a treadmill.

If you never plan to run outside, that training on a treadmill is fine. I'm starting over with my running and this time all my runs will be outside.

This is absolutely my experience, as well. Or, rather, I began on a treadmill, things were humming along fine. Then around week 3 I went outside for the first time, as the weather finally allowed it. It definitely seemed more challenging than on a treadmill, even though the literature says it makes no difference.

It wasn't such a big difference in my case, but it was definitely different. And more challenging.

The treadmill is "softer," you get a bit of a bounce off of it. Running outside means you are on firmer ground, your body has to absorb more of the impact. For those with knee or shin problems, this could make a difference. Good form probably matters more, as well.

If you are training for an actual 5k, make sure you run outside sometimes before race day. You may be in for a rude surprise...

--Prahasaurus

Today I walked 4mph for 30 mins with a jog of 20 seconds in between:)
CJ