Impressions (very mild spoilers)
Played a bit over 3 hours, just reached the 4th planet (though technically the 3rd with one of them being an arena type place) I feel I'm about 2/3 through the story, but I can't give a full estimate till I'm done. It's already longer than Q4B and FFA however. And looking at the trophy list, I'd say maybe 15 hours if you want to run through it a couple of times to Platinum it.
So far this game feels like a big improvement on A4O, Q4B and FFA (Qforce). It does feel like a streamlined ACIT. No ship flying (basically menu based) or Clank the Timesweeper puzzles, but there's a new gameplay segment in replace of Clank's previous puzzles which is kinda neat. Otherwise it feels like a traditional Ratchet game, which is a good thing in this case. There's not a whole lot of platforming here, but there are some new gameplay elements introduced (a couple which may remind you of some other games) that work well. The intro level, and the first 2 planets were pretty long and varied. Overall I've found it quite enjoyable thus far.
Graphics are good, I'd say on par with ACIT, but with a notable improvement in the lighting. Some areas it got a bit bloomy, but I feel it works well on the whole. It does feel like a 30fps game, but, I did not notice any major framerate drops on my machine. It ran smoothly most of the time for me, and while 60fps would be nice, I never felt the framerate to be a problem here. The cutscenes, while a bit compressed, look nice, and the music and presentation are done well. If there's one thing I have to say, it's that the even better lighting in the cutscenes reminds me of how good this game could have looked on PS4
Also in the menu there's an option for cloud saves, didn't check it out, but possible Vita version incoming? Anyhow, I think that's about it for the moment, will post again when I complete it. As it stands now, great game, Ratchet is back, and probably about the amount of content you'd expect for the price, but it's worth it. Buy it to support a PS4 R&C dagnamit