If I were you, and reading how you're going to be flying I would go with the dual tail.

Basically here is the deal. The stock motor lasts max around 20 hours, but more likely 10 or so. The DD tail should last double that, I've only flown about 60 or so flights on my dual tail, but it is still going strong, but that's not the longest test period. I've read several cases with the dual tail where people fly it just about every day and it's lasted 7 months or so.

The brushless would probably last longer than the dual tail by a bit, but the problem with the brushless is it has lower power and takes longer to spool up, is heavier so it creates balance issues, and it's alot more expensive.

Over all just whatever you choose =)

I wrote up an article a couple of months back. It probably needs some updating, but I'll post it here so you can read it and see what info you can get out of it.

If you do the dual tail or the DD make sure you fuse the tail motor.
http://www.heli-max.net/mediawiki/in...il_Drive_Setup