I have used CCH Online (base price ~$600), The TaxBook (avg. $300 - depends on the components you want) and also the beefy 6" x 9" US Master Tax Guide (~$200). The latter is my preference, because I have multiple screens open at once and I label those sections I need. It takes up very little real estate on my desk.

True, if changes happen after print - it would render the resource - obsolete??? but - by how much?

Seems, it's a personal preference - but if Inuit provided an online resource or collaborated with Wolters Kluwer and gave existing customers a small discount, I would definitely be on board.