I'm closing in on the end of Spellforce and will be looking to pick up RoA1+2 or M&M1-6 soon. From those who've played both, which should I go with?
I'm an old PnP gamer, manuals and maps don't bother me a bit. But what about battle tactics in each series? Do you have to place your party just right and have just the right spells/equipment (i.e. heavy preplanning of each combat), or can you survive most of the run-of-the-mill non-boss battles with a good general party layout and distribution? What are the other most important distinctions between the two rulesets?

During battle in RoA, it drops out of the '3D' view into a combat grid, where you move each individual character around to attack, cast spells, use items and so on with available AP (action points). Experience so far is that there is no warning for the majority of battles.
There is a huge amount of control/options in character creation that determines how each one behaves.
MM is all in the one view, monsters appear on screen and you group attacks in turns but as a single entity (you can't split the party), it's possible to avoid them and it's more of a case of hacking your way through them all with far less strategy than RoA.
MM1&2 are slightly different, no enemies on screen until a random encounter and you can position the party a little -fighters at front, spellcasters at back, that sort of thing- but it does not compare to RoA.
Characters are fairly basic, choose a class, learn skills, get better weapons and grind levels.
I'm currently playing MM1 right now, hand drawing out maps and all. Fun despite the clunkyness.
The games are different enough, so choose what you lean towards more in a RPG.