With regards to cleaning, unless you can clearly see significant marks on the mirror, I would not clean it. A small amount of dust will have no appreciable impact on optical performance. If in doubt, you could seek an opinion at an astro shop - take it in for them to look at.
You can easily clean the front (outside) meniscus corrector. First try a (lint-free) microfibre lens cloth by simply breathing on the plate and wiping - do small sections at a time. Only use cleaning solutions if that doesn't work (and there are plenty of threads and web pages on cleaning optics).
The Saxons are underrated regarding quality, IMHO. The MakCass design is robust and pretty decent - you can look up the fundamentals of telescope designs and various reviews. I think it makes a good planetary scope and at 6" you should be able to see the planets quite well plus doubles, clusters, etc. Deep Sky Objects (DSOs), like nebulae, galaxies, and so on, may be a bit of a challenge unless at a really dark site, but you can still try. That design is also fairly gentle on eyepieces. The longer focal length will mean that photography is a bit more demanding, but still doable. I think it's a pretty good "take anywhere" scope.
Edit: Oh, yeah, there's no user collimation with those scopes - there should be three collimation screws under rubber covers at the back, but you shouldn't need to touch them.
Don't spend too much on your first scope! Learn what you want to do with it first and how commited you are to astronomy. At least, that's my 2c worth.
