More or less the same, though 98 is better than 95 and NT4 is better than both.
I preferred 2000 over XP but accepted XP once I configured it to be more like 2000. With time I considered XP to be marginally superior.
I strongly resisted 7 over XP but accepted 7 once I configured it to be more like XP (thanks in large part to Classic Shell). With these changes I consider it markedly superior to XP but remain annoyed by some changes to infrequently used tasks such as the navigating the control panel. In most ways it is more user friendly and capable and much less glitchy.
Excepting missteps like ME and Vista, Windows has generally improved with each iteration. I'm not so hopeful if it comes to using 8 but admit I don't know much about it.