I have a Capless and I’ve played the Avalanche a bunch. Though they’re still in the same league in terms of play (Capless is incredible value for money!) I would personally consider the Avalanche to be an upgrade. It plays lighter than the Capless (not sure if they’re similar in actual weight; just talking about perception here) and grinds better.
I found that once I started getting into this “league” of yoyos, each new yoyo that I bought or tried started giving me the “yeah, it’s fine. But is it significantly better for me than the Capless?” line of questions. And the answer is typically “not really”.
I think the Avalanche is noticeably “better”, but not significantly. So when you’re talking about “upgrade” just keep in mind that it will be incremental improvements from here on out. If your expectations are set realistically, then you will probably enjoy a great many yoyos out there.
Take the Code 2 for example. It is more stable than the Capless. It grinds better. It has the Side Effect system if you dig that sort of thing (I think I do; just need different side effects so that I can really appreciate it). In all ways, it seems to be an “upgrade”. But to me, it’s more of a lateral difference. “Here’s something different than the Capless, and it’s awesome!” but not necessarily “Here’s a major upgrade to the Capless.”
All in all, I recommend thinking more in terms of trying something different than trying for an “upgrade”. Try to find something with a different profile, or which people claim has different properties. I hear the Berzerker plays heavier and has a mighty spin… awesome properties, and “different” from the Capless! On the other side, people LOVE the Dietz which is undersized and has a totally different profile than the Capless.
But I ramble. Whatever pricey yoyo you get will possibly be a slight “upgrade”, but will certainly at least be a “lateral” difference. Which in my opinion is still a great thing.