My wife never had any experience with anime before she was with me; over the years I've sent her scurrying out of the room with much of what I watch... Tenchi Muyo In Love, though, kept her interest piqued.
The animation: beautiful; the usual Tenchi OVAs and TV-series are great, but the movie is a real knock-out. Unlike the big-budget anime movies of late (and Disney films) the scenes have a consistent level of quality. There aren't nine scenes of good animation, and one scene of mind-blowing 3D computer-generated/cel combo stuff... all of the scenes are great quality, with little to cause distraction.
The storyline: good. It draws somewhat upon knowledge of previous events in the Tenchi realm, but is accessible for novices. I would have preferred the story to stick with the emotional aspect- as exciting as a big demon fight is, the characters are even more so... but then again, I guess that's why companies make stuff like Kimagure Orange Road or Maison Ikkoku.
The translation: good. Unlike how I prefer most of my anime, I'm both used to and accepting of the English translation job done by Pioneer. They're the voices I first heard when watching Tenchi, and they settle okay with me. (My wife can't stand Sasami's English voice, however.) I don't feel like I'm either missing parts of the original dialogue, nor do I feel like the story is too Americanized. If I were used to the Japanese version, my feelings might vary- but I have access to both versions, and the English one usually wins out.
The storyline is good... Tenchi as a whole is not supposed to be unique, but a comfortable, fun ride. It delivers entertainment in droves, and the characters are so well-rounded that it's hard not to come away without feeling affected, despite feeling like you've just watched a mish-mash of SF cliches. Rather than the tour-de-force movies like Akira or Ghost in the Shell, this is the movie I'd probably show new-comers- "This is what Japanese animation can be like." When they're more willing to work at comprehending a story, then move on...