I've been thinking about making this change for a while but wasn't sure if it'd be preferred by users, so this feedback is appreciated. :)

My thought was to replace the compact alerts view option with a "collapse all alerts by default" option. Though perhaps we could base this behavior on the tree? ie: maybe the perf tree default-collapses alerts. Or maybe base it on the number of alerts or something. 

I agree in general that we should probably try to move in a direction where we try to lean more towards having nice defaults instead of lots of settings. 

I think you should try to make the behavior just do the best thing without any checkbox. FWIW, I thought collapse by default worked well. If people are frustrated with being collapsed by default, then you can understand why and make it work better without a setting.

I think that's a good point. I suspect a lot of sheriffs might like having the alerts expanded though, so I do want to proceed making sure we don't break their workflow. 

One possibility to avoid settings could be to use the compact view functionality but have the alerts expanded by default? 

Though at least in the interim, I think changing the setting to "Collapse alerts by default" would be the least shocking for sheriffs. 

Sheriff for today, so adding my 2 cents.

Most useful parts of the cards for me are:
  - builders that have failed
  - how many builds have failed
  - whether there are comments to look at or not
  - What CL does Findit think caused this

Parts that I wouldn't mind if they were collapsed:
  - bugs (a count w/ links similar to comments would be good)
  - tests that failed (these are already grouped)
  - regression range

Thanks for the feedback! I like the idea of adjusting the collapsed view to show more information. I think with your list of things you find useful we could definitely fit things into a rather compact view. 

I also find it super useful to know that you don't find the full list of bugs useful to immediately see since that is something we do emphasize a lot right now. I think maybe something like showing 1 bug then something sort of "+ 5 more bugs..." text or something that you could click to see the rest of the bugs. 

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/50a8215674c965183529c5afedd01e39a4d7237e

commit 50a8215674c965183529c5afedd01e39a4d7237e
Author: Tiff Zhang <zhangtiff@google.com>
Date: Wed May 03 20:51:59 2017

SoM: Change compact view option into collapse alerts by default.

Bug:712085

Change-Id: I95c437123cb4b3c101901288738f8437402755b6
Reviewed-on: https://chromium-review.googlesource.com/490693
Commit-Queue: Tiffany Zhang <zhangtiff@chromium.org>
Reviewed-by: Sean McCullough <seanmccullough@chromium.org>

[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/test/som-annotations-test.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-drawer/som-drawer.js
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-alert-item/som-alert-item.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-drawer/som-drawer.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-app/som-app.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-annotations/som-annotations.js
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-app/som-app.js
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-settings/som-settings.js
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-header-styles.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-alert-item/som-alert-item.js
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-settings/som-settings.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-annotation-manager-behavior.html
[modify] https://crrev.com/50a8215674c965183529c5afedd01e39a4d7237e/go/src/infra/appengine/sheriff-o-matic/elements/som-bug-queue/som-bug-queue.html

 Issue 737312  has been merged into this issue.

Compact alerts view has been made default, and I think it's fine to keep the checkbox to toggle collapsing by default for now. 

I'm keeping https://bugs.chromium.org/p/chromium/issues/detail?id=658781 open as the main bug for tracking making Sheriff-o-Matic's alert UI better.