Magus Mystic Theuge Vs Arcane Trickster

[MrGodTear]

I'm looking for the pros and cons or building my Magus into either prestige class Mystic Theurge or Arcane Trickster.

Or if someone else has another prestige class that I should look into and might be interested in, go ahead and share.

My magus is strength based, so I didn't have to go Dervish Dance.

The campaign I'm playing in is a post apocalyptic futuristic style campaign so guns are easy to come by. My GM is using a bunch of undead right now so I'm looking Theurge so far, but I have left it open so I could go Trickster at a moments notice. There is a Paladin in our party so role plea wise it would make sense for me to go Theurge before Trickster.

I was thinking of going 6 levels into magus and then four levels into either cleric or rogue. Going 7 and 3 would be pointless because I'm a sylph, at level 9 I will be getting airy wings and fly places.

So far my only magus arcana that is set in stone is Spell scarrs.

If I go arcane trickster I get two rogue talents, and I was thinking of taking grit, since magus start off knowing all simple and martial weapons I don't have to get the exotic weapon feat for it (guns are simple weapons).

If I go Theurge, I will be getting Broad study no doubt and be able to spell strike cleric spells without spell failure since divine spells don't have spell failure. And buffs and debuffs during spell combat are nice.

[LoneKnave]

Taking these PrCs as a Magus is a huge mistake. That said...

You can get into AT taking 0 rogue levels. Either by taking the Greensting Slayer Magus archetype, or taking 1 level of Snakebite Striker Brawler, and that feat that increases your SA by 1.

[Corvino]

Mystic Theurge has once again become a horrible choice with the "no SLA for early-entry" change, which for a brief moment allowed them to shine. They're not worth it as a full caster, and even less worth it as a 6/9 caster. There are negligible pros and massive cons.

I'm not sure on the entire Arcane Trickster thing, though again I get the impression that they work better with full casters than 6/9 casters. There are now more ways to get early-ish entry for best results though, which is a plus.

[BigDTBone]

Spellstrike with harm? Yes please.

[Kurald Galain]

Greensting slayer is horrible. It's much better to take one level of Snakebite Brawler, then use the feat for +1d6 sneak attack.

Yes, arcane trickster can work; you basically trade your arcana and class features for sneak attack dice, but some spells and arcana specifically boost and enable these. Mystic theurge doesn't work too well on a Magus, really, except for the part where you spellstrike with Harm :)

Here's a Magus guide for you :)

[Mysterious Stranger]

The biggest con of any prestige class is they are generally less powerful than a single classed character. This is particularly true with spell casting classes with class features. If you have to multiclass to a class this becomes an even worse option.

The biggest pro of a prestige class is they often allow you to do cool things that no other class can do. These cool things are usually less powerful than the original class, but often fun anyways.