А здесь список изменений
Вытянул только summary, по ссылке есть более подробное описание каждого пункта

Summary

* Release
o F# is integrated into Visual Studio 2010 Beta1
o F# in Visual Studio2010 can build applications for .NET 4.0 Beta1
o Updated F# CTP for Visual Studio 2008 and .NET 2.0/3.0/3.5
o F# PowerPack is a separate download for Visual Studio 2010
o F# binaries compiled with this new release are incompatible with binaries from previous releases, so must be recompiled. Binary compatibility for F# is an aim of the RTM release of Visual Studio 2010.
* F# Language
o #light is the default
o Support for calling and exposing .NET ParamArray parameters (‘params’ in C#)
o Performance improvement for Sequence Expressions
o Units of measure support for signed integral types
o Support for custom numeric types (123X, 1.0R, etc.)
o Overloading tie-breaker rules result in fewer ambiguity errors when calling overloaded members
o “?” operator enables definition of dynamic member lookup
o Attributes can be placed on implicit class constructors
o Let bindings and implicit constructor parameters in type definitions only generate fields when necessary
o Curried members are generated as un-curried .NET members
o Support for InternalsVisibleTo
o Support for all Assembly*Attributes
o Type augmentation members are now only intrinsic when declared in the same namespace and file
o The ‘null’ literal now generalizes
o Structs are now analyzed for nullness based on their contents
o F# record and union types implement the new .NET 4.0 interfaces IStructuralEquatable and IStructuralEquality
o Indexing and Slicing is now supported up to Rank 4 arrays
* F# Core Libraries
o FSharp.Core.dll API naming standardization resulting in a handful of API changes
o Silverlight2 version of FSharp.Core.dll available in the CTP Update
o RequiresQualifiedAccess applied to many of the modules in FSharp.Core.dll to prevent opening the module in client code
o BigInteger/BigRational changes

o Structured Formatting Customization for %A and FSI display

o ResizeArray module moved to F# Power Pack
o IStructuralHash removed, IStructuralEquatable and IStructuralComparable added
o [.Net 4.0] FSharp.Core.dll is SecurityTransparent and can be used in partial trust
o [.Net 4.0] F# uses new .NET4.0 Lazy and Tuple types
o [.Net 4.0] Async.StartAsTask and Task<>.AwaitValue convert between F# Async and .NET4.0 Task
o [.Net 4.0] Array.Parallel.* functions provide data parallel versions of common array operations
* F# Compiler
o Fsc.exe command line compiler options cleanup and standardization
o Passing mscorlib and FSharp.Core.dll explicitly is supported, and defines the targeted runtime
o Optimizations for Sequence Expressions
o Optimizations for Tailcalls
o Optimizations for Curried Methods
o Optimizations for Class Representations
* Visual Studio
o Error List populated by results of Build as well as background errors
o Performance improvements in F# Visual Studio language service
o Many improvements to debugging in Visual Studio, including breakpoint setting and data visualization.
o More reliable F# Intellisense in the face of incomplete or incorrect code
o Improved project build and rebuild performance and reliability
o QuickInfo on #r shows details of the referenced assembly
* F# Interactive
o F# Interactive displays all bound values
o Simplified command line format for fsi.exe makes it easy to execute simple F# scripts with “fsi.exe script.fsx a1 a2”
o Fsi.exe emits debug symbols, so can be attached to, to debug a running script
* F# PowerPack
o Additional Async utility functions
o An API for accessing F#-specific metadata from F# assemblies — FSharp.PowerPack.Metadata.dll
* Miscellaneous
o Beta F# Language and Compiler documentation on MSDN
o Deletion of features deprecated in previous F# releases
o Plus many, many more minor fixes and improvements