Hey,
Ideal title for this post

a long process indeed, and everyone has there own ways of approaching and completing this process.
Flatiron looks like an impressive tool, im not a Max user so I cant comment on it really. The same company makes Unwrella for Maya which is an auto unwrap tool, I have done some tests with it and it seems great on organic models but im not as convinced with hard surface models. C4D has bodypaint for its UV unwrap which i have only used breifly, so the C4D users can probably give you some better info on that.
Over time i have found 3rd party unwrap tools to give the most help in this part of the process (i.e unwrap3d, uvmapper, roadkill, unfold3d--which is now intergrated into Maya, UVLayout, to name a few)
My choice 90% of the time Headus UVLayout

but in saying that every model and every user has a different method and really is what suits.....sometimes a one click automatic map straight out of maya can be right for the model you have.
Baking, ahhh yes! my preference....Sunday afternoon, simple sponge, double layer, jam and whipped fresh cream and a dusting of icing sugar to finish. Kettle on, cup of tea.......

ok seriously.....
Never worked with Max, so you know better than me

C4D has a very straight forward baking system in the built in renderer, i found it super easy to use (same goes for most things in Cinema

which makes it a good choice )
Haven't actually done anything with Turtle for Maya, never felt the need really, if Christian is recommending it, i'd take that as good advice! Mental Ray in Maya is what i use a lot of the time, works for me, lighting, AO etc i always get the results im after. Im currently beta testing VRay 3 for maya but havent got round to doing any baking yet, looks like a full featured toolset though

I know there are plenty of 3rd party options you can look into, XNormal is very easy to use and very quick for AO baking, worth looking into if thats specifically what you are baking, it does more but I use it mainly for quick AO bakes......and its FREE
and this is why i say the post is well titled "long process". Everyone has different tools and different methods, you have to find the pipeline that is efficient for you and how you work. as a 3DMax user it will be completely different to mine as a Maya user and that of other people here who use a whole manner of different software tools. I never baked anything out of Maya when I started using Ventuz, and it took me the best part of 18 months to really make the whole process work for me.
ok so hope i didnt go on too much

Hope it helped
Chris