My first-glance opinions:
The prestige class is very hard for me to say whether it could be too good or too bad. It doesn't seem at all to be for casters: you need only 1 level in the arcane class, you get full caster level advancement but 3 spellcasting levels only, and that's exactly great for a character with only a minor arcane ability. For a mostly-wizard or -sorcerer this PrCl is very bad.
If you were a fighting class, you would give up 4 points of BAB in 11 levels (including the arcane level to qualify) for all the nifty defensive abilities and +6 in Strength.
It's hard to say, there are too many advantages and too many disadvantages at the same time. However I can say that I don't like the gp requirement to acquire the new level special features, and how this acquirement is tied to in-game quests (harvesting the special material). That may seem to be an interesting adventure suggestion, but after a couple of times it can seriously bother the gaming group...
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About feats I had great expectations. I know these are only very few of them but I am so far disappointed
Double-Wand-Wielder and Reckless-Wand-Wielder are definitely "new" and interesting, but the first one seems clunky. It occurs to me that they wanted to try something new but they are terribly scared that it could be too good, so they stacked penalties one after the others... Ok that you need 2 feats to qualify, but why 2WF? It has only a partial relationship with using 2 wands, and I seriously doubt your wizard is EVER going to use that 2WF for anything else than qualify for DWW. However, I would accept this requisites even if they are IMO not very well-designed. But then they even add the extra charge cost. No way...
Touch Spell Specialization is almost a reprint of T&B Spell Specialization (which however worked only on Rays or Energy Missiles). At the time of T&B I really thought that the +2 bonus was too small except at very early levels, and I was absolutely sure that WotC would have changed Spell Specialisation into something surprising and useful, but I was wrong.
Practice Spellcaster is fine, we knew it already, no problem for me if 1 feat is in 2 books, as this doesn't seem to be too common.
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The new and revised spells sound nice instead. Maybe too many new destructive spells, I don't think there was a real need for them

and I wonder how different they prove to be at the end. However almost all the non-damaging spells seem fine to me. Some are pretty powerful, but of course we have to check the details first.
I am specifically fond of the following:
Assay Resistance: thank god, after 4 years a spell to help vs SR!
Duelward: probably not overly useful, but anything helping counterspells to be actually part of the game is welcome
Anticipate Teleportation: supposing that the predition part of the spell lasts enough for the spell to be useful, this could be quite fun
Servant Horde: usually I don't think more than 1 US is needed, but there may be interesting applications
Phantasmal Assailants: a spell that damages Dex and Wis at the same time is definitely weird but interesting...
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About the new forms of potions and scrolls, well I think this is exactly the sort of flavor that I like in a RPG book. Something which is usable in possibly every campaign, and makes the game less predictable to the players without complicating the rules (for that there is tons of crunchy bits already). For the little space that it takes in the book, I only wish they had put double these ideas, and didn't stop at potions/scrolls.
Finally the Contingent Spells seems a very nice extra, they are basically automatic potions which you cannot share with the others. I think they could be a very solid tactic in a caster's repertoire, especially a cleric.