Re: Gibby's vs. SD Antquities
No experience with 490t.
I have Ants in a 1997 Les Paul 1960 Classic, replacing the 496r/500t Hot Ceramics. Major change. I liked the tone of the stock pickups but they were too hot for my amps and my style. I love the Ants.
I have Seths in a Les Paul Supreme, replacing the stock 490r/498t. 490r is muddier than Ant or Seth, very warm, nice for jazz. I like it, it's usable, but it does not blend well with the 498T. Seths were a major change, more vintage, better choice for me. Love the Seths. No clear preference for Ants vis-a-vis Seths.
I have '57 Classics in my Les Paul Elegant and my 335s. Not feeling the need to change from the stock pickups. Warm, yet can be a tad grainy. Close to Ants/Seth. Prefer '57 neck to 490r. Good for variety of genres, but there are better choices for rock/metal. Not as much clarity and string separation as Seth/Ants.
I also have A2 Burstbucker 1 & 2 sets in my Historic Les Pauls. I like them, doubt I would ever change them. More clear than '57 Classics, more edgier than the '57s and Duncans. On a rock gig, I prefer the BBs over '57s. I like the '57s over the BBs for jazz, or gigs where there might be a lot of older people who would not like the edginess.
These are all just different flavors...which Baskins & Robbins chocolate ice cream do you like the best?
Do you love the tone of the Ants in your 335 clone? If yes...leave them in there!
Do you love the tone of the Paul and the 490s? If yes, leave them in there! If NO, then it is time to change them.
Decide whether you need the same tonality from both guitars. (I like having a Number One-A, a backup for my main guitar.) So adding another set of Ants should be good. They're hard to beat.
If you are looking for something a little different but still PAF, you can go WLH, SNS, PGs or '59s...plus those from 30 other brands. Or perhaps something "more" like JBs or a version of the Custom for agressive styles. You don't mention loudness levels, genres and amps, but those factored heavily in my decisions.
Work out who you are as a player; your answers will become clearer.
But it's hard to go wrong with Duncans. I hope this helps.
Bill