Find Mailboxes in Exchange on Different Attributes

Find mailboxes with manual quota enabled.
Get-Mailbox | Where {$_.UseDatabaseQuotaDefaults -eq $false} | Select Name, IssueWarningQuota, ProhibitSendQuota, ProhibitSendReceiveQuota

Find mailboxes hidden from address book.

Get-Mailbox | Where {$_.HiddenFromAddressListsEnabled -eq $True} | Select Name, HiddenFromAddressListsEnabled

DB retention
Get-Mailbox | Where {$_.UseDatabaseRetentionDefaults -eq $False} | Select Name, UseDatabaseRetentionDefaults

Send on behalf access
Get-Mailbox | Where {$_.GrantSendOnBehalfTo -ne $null} | Select Name, GrantSendOnBehalfTo


Get-Mailbox | Where {$_.AntispamBypassEnabled -eq $True} | Select Name, AntispamBypassEnabled

Get-Mailbox | Where {$_.RulesQuota -ne "64KB"} | Select Name, RulesQuota

Source:
http://exchangeshare.wordpress.com/2008/06/11/find-exceptional-mailboxes-in-the-exchange-environment/