The problem with the TIE advanced was that it was a ship built focused on defence. Not inherently a problem, but for a 'tank' to work, it needs to draw fire onto itself - and X-wing has no real mechanics for forcing you to fire on a given target, or blocking lines of fire, aside from special rules associated with specific pilots or upgrades (none of which biggs, tactical jammer, shield projectors, draw their fire on generics - were available to the TIE advanced).
The Raider does come with an additional TIE advanced model, as well as new pilots (some of them
very good).
The TIE/x1 title is awesome - advanced targeting computer is more.....good if you know what you're doing with it. It's pretty easy to make good on Vader, because of the free action, and an easy choice on Maarek Stele, because his special ability triggers off criticals, but for other pilots it's far from the automatic choice. Fortunately, the Systems upgrade is one of the most flexible and powerful in the game, and accuracy correctors, advanced sensors and sensor jammers can all have a use.
Hell, even advanced scopes could be useful - I've never tried it, but given Zertik Strom's ability, moving first with intimidation might make for a nasty blocker. Not advocating it as the best thing since sliced bread, but it's far from useless.
As to Engine Upgrade - it's the default choice, but MkII engines aren't bad either. The TIE advanced's weakness in manoeuvres is that its green dial is pretty shoddy; Vader is very vulnerable to getting stressed because he has trouble shaking it off again compared to a TIE interceptor. It's the same reason I've seen quite a few people use the Elite slot for Adrenaline Rush, letting him carry those lovely two actions through a koiogran turn.
Also, if you can get some, I'd suggest looking into Proton Rockets. They also are a weapon very much made with the TIE advanced in mind; only range 1 but very few things can ignore a 5-dice focused attack - and suddenly people want to avoid a head-to-head joust with you rather than seek one.
The TIE advanced is an odd beast; it doesn't have the firepower to joust nor the manoeuvrability to arc dodge. What it does have, however, is decent toughness, some of the best pilots going (including arguably THE best pilot in the game), and massive customisability.
I bought enough to play 100 point games for both sides, and then decided to focus on Empire until I get all the ships I want, then start getting Rebellion, and then finally Scum. My next purchase will likely be another Tie Fighter, Tie Bomber, or Tie Defender.
From that list I'd suggest TIE Fighter. If you've only got the core box, then you have yet to encounter the glorious terror that is the Empire's finest TIE/ln pilot, OS-72-1, Civé Rashon, call sign "Howlrunner".