...Seems like the war is on!!!!...
One of whom just got them, the other of whom has been using them for the past three levels. And has more of them. And casts them at a higher caster level.
As if it matters how many one has in such a duel!!
Lets just say the Arcane Trickster has a racial substitution like "Elven Wizard"
(RotW)
and has a couple of 9th level spells... Its more than enough.
They cast with the same caster level - Practiced Spellcaster Feat, (Complete Arcane).
Oh noes, you'll survive Fireball, widely regarded as the best spell of all time. If you're a spellcaster, you could just use Resist Energy or Protection from Energy and get protection that way.
Oh you can go ahead and lose those rounds casting your resist energy and protection from energy... on the house
The difference between a d4 and a d6 is, what an average of 1 hit point per level? You'll end up, what, 13 hit points ahead assuming equal Con?
Not even that.
You got me there... thought the Trickster had d6, but he's got a d4 like the wizard.
They are both well bellow 100 so Powerword Kill works just fine

Guess i won't be needing that extra 9th lvl spell after all.
As i said earlier... highest initiative wins...
I think its safe to assume that the Trickster has a better Dex modifier and that he has more chances of going first! (I'd even say he has the improved initiative Feat as well but you can argue that your wizard has that as well... even though chances are you 'll find this feat more often on a Trickster than a Wizard...
Reflex is generally regarded as the least important of the three saves (most important being Will, second being Fort). While having a good reflex save isn't a bad thing, it's also not the best thing since diced turnips.
Sure. Still that is a plus for the Trickster. Don't forget Evasion!
Yes... it is impossible to counterspell skills. Here's a better question: what skills are relevant at such high a level?
Never said anything about counterspelling "skills". I said that its impossible to counterspell the trickster.
What skills are relevant? if not all, here are two: Bluff & Sleight of hand
Why?
ConCeal sPellCasTIng [ManIPulaTIon]
You can cast spells without others noticing . Prerequisite: Concentration 1 rank, Sleight of Hand 5
ranks, Spellcraft 1 rank . Benefit: You can cast a spell without revealing that you
are doing so . Make a Sleight of Hand check as part of the action used to cast the spell, opposed by the Spot checks of onlookers . If you are successful, an observer can’t tell that you’re casting a spell . That observer cannot make an attack of opportunity against you for casting, nor can it attempt to counter your spell
false TheurgY [ManIPulaTIon]
“How’s that magic missile feel? I’m sorry—did you think I was casting sleep?”
Prerequisite: Bluff or Sleight of Hand 8 ranks, Spellcraft 8 ranks .
Benefit: As a swift action when casting a spell, you can adjust the spell’s verbal and somatic components to mimic those of another spell of your choice of the same level . Any creature using Spellcraft or any other means to identify the spell you’re casting believes it to be the other spell instead .
This trick renders your spell immune to the normal method of counterspelling, though dispel magic or a similar effect still works normally . Of course, once the spell takes effect, it can be identified and dealt with normally (a fireball still looks and feels like a fireball once you’ve cast it)
Both are Skill tricks found in Complete Scoundrel.
Given that blasting is rather suboptimal, I'm happy to let you have your BAB.
Thank you
...
Thing is that as much as I really like certain PrCs... at the end of the day i really wish they didn't exist at all! Its cases like this that make me look back to previous editions... Trust me I LOVE the straight Wizard... as I LOVE the straight Rogue... problem is they are overshadowed by powefull PrCs.
Come on! how many people do you know to take a straight class beyond 10th Level (or 7th or 8th) nowadays?
...OK PrCs offer variety customization blah blah blah... the least they could do was to keep the main classes "in the game"...