Legacy Update is a better option for Windows 2000 and later as it uses a proxied Windows Update 6 implementation. Windows Update Restored uses Windows Update 3.1 and is better for Windows 95/98/Me and Windows NT4.

Legacy Update doesn't support Windows 95, Windows NT 4.0 SP3+ Windows 98 First and Second Edition, Windows Millenium Edition.

Windows Update Restored (purportedly) does.

For context: https://legacyupdate.net