I haven't tried many alternatives but can say that the primaluna Evo 400 I own is a great integrated amplifier that doesn't run the tubes hard and is made to last.
Plenty of good reviews around.
The only downside is that the 8 power tubes are costly when replacing...cos there's 8. To my ears the kt150's sound better than the el34's it came with driving IMF RSPM IV transmission lines.