Estes is a 'no-brainer' - especially as they reintroduce their older kits to some of us who'd gotten away from the hobby for awhile or couldn't afford the cooler ones back when we were kids...
But I'd like to put in a special plug for Quest's kits too - they've offered very good value for the money compared with Estes, and I have especially appreciated their inclusion of the Kevlar cord for protecting and anchoring their shock cords.
Recovery system problems have always been a problem in model rocketry and it is difficult for me to understand how Estes can still be using the same abysmal shock-cord anchoring system and melting elastic that failed so often on my rockets as a kid almost 40 years ago. I was so impressed with Quest's Kevlar cord idea, that I now incorporate it into every rocket I build - even Estes' kits.
Combining that with a small square of Nomex paper wrapped around my chute or streamer has practically made recovery system failures a thing of the past.
That said - the real answer to your question doesn't lie with any one brand or another - what gets me to buy a new kit is to have something different - not the usual 3FNC rocket designs that became boring even as a kid. Whether it is a sleek new futuristic design, or a new recovery system concept - I'm always looking for something 'different' to build. This past summer it was "Night-fliers" - rockets with built in lighting that could be flown and recovered after dark.
Yitah Wu's new XTRG design fits the bill beautifully too as a "new" concept that I think will intrigue a lot of builders.
So that's my recommendation - carry the staples, but stay on the lookout for things to bring us that will be new and different in the hobby.
(not really, I just want to get my post count up) ASP kits are great for competition Semroc is great for traditional kits Flis has the most innovative kits
