I've never been interested in having Exchange in my phone's email client because the email clients built in with most Androids suck.. I bought Touchdown years ago because it was built to talk to Exchange and it worked very well.
Gmail is pretty good, but I'm still not interested in merging my Exchange account with it because then my phone becomes completely subject to my workplace's rules and regulations on mobiles. Touchdown keeps that separate and I like it that way. Hell, I have a company phone and I STILL use Touchdown. If some idiot Exchange admin F's up a powershell command to wipe some dude's phone and ends up wiping everyone named Steve's phone**, I don't have to worry because only my Touchdown partition is affected. And any personal stuff I have on the device (for better or worse) is unaffected. Yay.
**This HAS happened at a company where I warned the head of IT that the guy they just made a domain admin was not ready for that responsibility. Not a week goes by before he force wiped all phones belonging to anyone named Christine. Out of 1200 users. Fun day!