Adding my voice here just so there's YET ANOTHER post:
Due to the nature of our workflow/customer needs, we need to manually touch each order in Shipstation before printing the label. My time per label has doubled. DOUBLED. Because of laggy pop-ups and slow field response. That's not including when the entire site locks up on Chrome (with Cache flushed, rebooted, everything) and requires a force quit of the tab and a new login. I needed to print only 10 labels today. That's a miniscule day for us. The site locked up 4 times. 4 times!! How is that acceptable? There is NOT ONE SINGLE THING in the forced v3 upgrade that makes this more usable for our business. Nothing.
Also, reading through the forums it's clear I'm not alone, and it's also clear that there is no clear communication back to the user base about fixing these many, many, many issues - whether that's timeline, things that are not intended to get fixed, or ways to work around the many flaws in v3.