Common improvements:

SSE2 support
Higher limits
Max CPU threads bumped to 32
Cleaned up common code
Large Address Awareness

Slammin' Hammer 5.2

Enabled Visual Styles 6.0
Entire program now uses your default system font, instead of the dated win9x standard font
Revamped entire user interface, options menu is cleaner, removed obsolete options
Added new graphical options to the 3D View tab, including picmip, MSAA level, etc
Added an option to change the 3D viewport background colour: default is 128,128,128
Performance upgrades
Removed huge amounts of deprecated icons, cursors and bitmaps
Modernised large chunks of code, doesn't really affect the end user experience, but it should make you happier to know
Increased the distance that vertex positions are rounded to integers to 0.01 from 0.05, this fixes some gross vertex rounding issues (or lack thereof)
Say goodbye to the process window, Hammer's built in compiler now feeds compile information to a new exe, meaning no more freezes, and instant compile information on the fly. You can still use Hammer while a map is compiling
New toolbar, transform tools. Same as the options available in the "tools" menu option, just brought out for ease of access
Texture application window is now more concise, added X and Y buttons that randomise texture coordinates for their appropriate boxes
Texture application window is now host to an experimental "reset" texture button, which resets the texture's scale, shift coordinates, lightmap scale and rotation
Reworked the entire right-hand UI bar to be easier to use
Removed Radial Culling, it crossed me for the last time
Removed Quake, Hexen 2, Quake 2 and Half-Life support
Added support for func_instance_origin, set the in-editor origin point for instances (no keyvalues needed)
Additional: Removed support for WAD files entirely
Clamped framerate to 60hz from 100hz (will make this an option)
Extended available automatic visgroup types
The "default animation" keyvalue for dynamic props is now registered and will now automatically play in the viewport
func_detail_blocker entities are displayed accurately in Hammer, with detail objects inside the entities' volume not being drawn
Added "open source" and "explore to source" buttons in the texture browser, selecting a material and using either of these buttons will bring you to the material's folder
Certain UI elements such as the entity report dialogue now support resizing
Models no longer share animations with all other model instances present
Multiple precision and accuracy fixes in general, brushes are less likely to crap up, texture coordinates are displayed correctly, etc
Paste & Paste Special shortcuts now properly displayed in the edit menu
Added support for the "boolean" FGD data type

Note:You don't have to use

Slammin' Source Map Tools's

Hammer to use its compile tools.(AKA you can use

Hammer++ with slammin' VRAD,VVIS,VBSP).

Note:Also

Mapbase's VBSP has most of

Slammin' Source Map Tools VBSP's improvements.

Slammin' VBSP

Power of 4 displacements are properly supported now
Detail brushes now preserve their smoothing group
Any prop with $staticprop can now be a static prop
Improved brush precision
Added missing content types to csg.cpp
New %compile command for VMTs, "%compileNoShadows", makes a material not recieve shadows, only direct light, this is used on water usually
Translucent brushes should no longer cut visleaves if they are world brushes
Any prop with $staticprop can now be a static prop (IE physics props)
Increased detail sprites limit
Custom lightmappedgeneric shaders are supported now
Implemented support for func_detail_blocker
Leaktest is now enabled by default

Commands

Note:This only lists new commands or ones that have been changed.
- -noleaktest disable leaktest
- -maxluxelscale, lets you limit the maximum luxel scale in your map
- -nodefaultcubemap, disables automatic skybox cubemap generation
- -blocksize, lets you customise the size of visleaf splitting "blocks", default is every 1024 units
- -visgranularity, lets you automatically place hint brushes in your map, syntax is "-visgranularity X Y Z"
- -infoladder, converts all func_ladder entities to info_ladder

Slammin' VRAD

enabling -worldtextureshadows

-ambientocclusion enabled vs disabled

HDR is enabled by default
Improved displacement lightmap quality
-staticproplighting, -staticproppolys and -textureshadows enabled by default
-final has been completely re-worked -aosamples is set to 32, -extrasky is set to 16, extrapasses is set to 8 and large disp sample radius is enabled
Transparent textures loaded by vrad are now bilinear filtered, for more accurate shadows

Commands

Note:This only lists new commands or ones that have been changed.
- -ambientocclusion, adds ambient occlusion to your map
- -aosamples to decide how many samples you want
- -aoscale scale ambientocclusion's strength.
- -softencosine, softens coloured lighting so it blends more accurately
- -coring, scale the light threshold before a luxel is completely unlit, used to save lightmap data, default is 0.5
- -dispchop, adjust the amount of patches generated for displacement faces, default is 8
- -ambient, when supplied with three RGB values, will apply a constant light value to every luxel in your map
- -reflectivityscale, multiplier for the reflectivity of textures in your map
- -extrapasses, lets you scale how many extra passes you want your map to go through, default is 4, differences above this value are extremely minimal
- -worldtextureshadows, allows world polys to cast texture shadows, much like models can
- -translucentshadows to enable the effect on $translucent surfaces

Slammin' VVIS

Minor code cleanup

Commands

Note:This only lists new commands or ones that have been changed.
- None?

Compatibility

Branch:	Compatible:	Note:
Mapbase	YES	Use Mapbase's VBSP
Source 2013 Singleplayer	YES	NONE
Source 2013 Multiplayer	YES	NONE
Team Fortress 2	YES	You need to install for it to work.
Garry's Mod	YES	You need to install for it to work.
Counter-Strike: Source	YES	You need to install for it to work.
Day of Defeat	YES	You need to install for it to work.
Source Filmmaker	YES	You probably need to install for it to work.
Left 4 Dead	NO	NONE
Left 4 Dead 2	NO	NONE
Portal 2	NO	NONE
Counter-Strike: Global Offensive	NO	NONE