Are IRAs & 401(k)s GOLDEN?

I have searched, and searched, and searched again. The best justification by proponents of the mantra - that qualified plans like, IRAs and 401(k)s are OUTSTANDING for retirement is - you get a tax break upfront and your money gets to compound on a tax deferred basis. They claim that DEFERRING taxes until retirement is advantageous because those nest eggs will likely be taxed at lower rates – Who