UKanDo Viewer has all the features included with the standard Second Life™ Viewer.
I do try to keep UKanDo up-to-date with this, so as and when new features or fixes are released, it normally only takes a few days for them to find their way into UKanDo.

You might also want to check the Release Notes as I often forget to add to this page!

Extra features added by me will be listed below as they get added to the viewer! 
In alphabetical order:
  • Alpha and Invisible Texture Options
  • Advanced Build Options with New Floater for Build Menu and Build/Edit floater
  • Area Search for Objects (Overhauled)
  • Auto Push/Pump Camera on collision Option to disable
  • Automatic Update Option (enabled by default)
  • Button Toolbars Alignment Options
  • Camera Viewing Angle uses Penny Patton's as Default
  • Cat Mode (Head follows camera) disable by default
  • Chiclet bar and/or Notifications Alignment Options
  • Client-side Pose-Stand
  • Colour picker Enter/Convert Hex, LSL or RGB (Copy LSL colour vector to clipboard button)
  • Delete all scripts from selected
  • Disable Min/Max Camera zoom distance
  • Estate Owners/Managers Freeze/Unfreeze and Eject/Ban to the context menu in the People floater
  • Estate Owners/Managers "Teleport Home" and "Estate Ban" + "Eject" and "Ban" added to right click menu
  • Expand/Collapse Build Window button
  • Film Menu with Show/Hide option in Prefs!
  • Flickr Uploads
  • Flip Texture checkboxes Restored
  • Geometry overload limit option [Preferences Graphics] to Protect against excessive geometry overloading your graphics card
  • Group/Role show UUIDs with Copy buttons (group's General and Roles panels)
  • Higher precision for building by numbers
  • Highlight Hidden Groups
  • HoverTips show/hide option - Advanced Menu
  • Inventory Attachment Editing
  • Inventory Allow copy and paste of worn items
  • Inventory Quick-Filters
  • Inventory Worn Items tab
  • Kokua Viewer "Refresh Scene" option.
  • Materials: Duplicate Values button (Syncs settings between Diffuse, Normal and Specular maps)
  • MiniMap Major Upgrade - Now more useful
  • Name Tag text colour picker
  • Pivot offset on root build options
  • Prim Alignment Tool
  • Private LookAt/PointAt - includes names on crosshairs option
  • Quicktools Button and floater
  • Reset Scripts, Delete Scripts and Refresh Content buttons [added to Build floater - Contents tab]
  • Return to last location from inventory
  • Rez using Land Group Option
  • Right click open Contents on worn attachments
  • Right Click Texture Refresh
  • RLV (Disabled by default, RLV menu hidden) [Avatar-> Preferences-> Setup] to Enable
  • Save inventory scripts as Mono
  • Show each avatar's age in their name tag unless they are older than the number of days specified in preferences
  • Show / Hide RLV Menus in Toolbar Option (only when RLV is enabled)
  • Shows the total member count on the Group panel's General tab if you're a member of that group.
  • Skin Change Options on login panel - Show/Hide option in Prefs!
  • Status Bar - Hide/Show Avatar Offset Slider, Draw Distance Slider, Marketplace & Buy Currency buttons, FPS(Clickable) and NetStats Graph(Clickable).
  • Teleport to Ground button
  • TimeZone SLT or Local Time/date ((Default SLT) [Top Menu –> UKanDo])
  • Turn to face camera when walking backwards Option
  • UKanDo Support Group Menu Option. Opens group profile or starts group chat if member
  • Windlight Settings by Penny Patton
  • WindLight Skies Crossfade Option