Managed extensions for VCL is the best components suite for .Net interop for Delphi and C++ Builder.

Managed VCL can:
* Create .Net objects from assemblies not registered for COM, using assembly name or location,  and loading .Net assemblies from streams;
* Create and use .Net objects that are not COM visible;
* Create .Net objects using parametrized constructors; 
* Call properties/methods/fields of .Net object including static properties/methods/fields;
* Handle .Net exceptions and get all .Net exception properties including exception type name, StackTrace etc.;
* Get information about loaded instance of .Net framework such as memory usage and size of heap by generation;
* Load needed .Net runtime and even select which version of runtime to use on startup;
* Place .Net controls on VCL Win32 form;
* Use ADO.Net datasources as TDataSet descendants in Win32 applications. ADO.Net will be native and most supported API for SQL Server 2005 (Yukon);
* Host ASP.Net pages and services;
* Embed .Net assemblies into Win32 application as resources.
Managed VCL can not:
* Query .Net interface if it is not COM visible.
* Work with .Net events. 
* Managed VCL will not turn your Delphi or C++ Builder into .Net language and it some other features may not be available.
Managed VCL includes special components for:
* ADO.Net - supports almost all ADO.Net features. Components to work with all standard .Net providers (those that are available in .Net framework) are included. ADO.Net will be most supported interface for MS SQL Server 2005 (Yukon).
* JScript.Net - lets you execute JScript.Net scripts from Delphi/C++ Builder application.
* ASP.Net - process ASP.Net pages and services from Win32 applications.