I see you are new to the board ... first of all welcome! Second, let me just assure you that you will not get a definitive answer to your question. If you had asked "what should I get, an ART Tube Pro or an Avalon 737?" you probably would have gotten a straight answer. Probably.

All three are legit pieces of gear, and everyone will have their own opinion. Best case scenario is someone else here has that same mic and has tried it with one or more of those pres. If possible, demo them yourself with your mic and pick the one you like.

Also, keep in mind that the Avalon is a channel strip and includes a compressor and EQ. Plus, the Summit has two channels. In some ways you're comparing apples and oranges.

I have a 737 and like it. But, I can't really compare b/c I've never used the other two.

The Avalon is beautiful for female vox. At least from what I've experienced.

But I've actually heard some wonderful female vox come through a Focusrite OctoPre too believe it or not.

Totally different animals though.