I've got an ETX-125 and they're pretty good for their size, but you can't expect too much when you're looking at DSO's because of the small apature. You should be able to get good views of the planets, but it depends on how much light pollution there is and what the seeing conditions are like. On a reasonable night you should be able to make out the Cassini Division in Saturns rings.
Have you done an out of focus star test? That should tell you if collimation is ok or not. I don't think your Newtonian laser collimator will work on a Mak Cass, I've never used one and am no expert on these things.
Check out this site for information about your ETX:
http://www.weasner.com/etx/menu.html
There's heaps of information there about servicing and tuning up an ETX. There's also instructions there for updating the software in the Autostar controller, it's certainly worth doing if it's an older version, it stops things like "rubberbanding" in AltAz mode which was a problem I had with mine at first.