Ask HN: In a post Sparrow world - how to manage multiple GMail accounts on Mac?

I was a big fan of Sparrow and paid for it right when it came out. Unfortunately, I haven't been able to find a suitable replacement. There are two problems I face:

1. Huge inboxes (10,000+ emails) - I do keep most/all emails archived, but that won't help with a mail client since even the Archive is part of the index. (My workflow is to deal with an email conversation and hit archive on the gmail web interface, this way I keep my inbox clean)

2. Need to use features like search, labels, etc.

3. Multiple gmail accounts (4 at the moment..)

I tried keeping 4 tabs open in Firefox with tab grouping but over a period of time the browser would really really slow down.

I've tried Mailplane but it is very buggy (keep getting errors of being logged out - especially when composing new emails). It's also very slow in terms of marking things as read (I open an email and my notifications will still say that I have the same number of emails read)

With Mail I had the issue of the system really slowing down due to the huge number of emails.

The last version of Sparrow also has the same issue but not as bad as the mac Mail.

So how does everyone on HN manage their multiple gmail accounts ? Is it really still such a struggle or am I missing something ?