The upgrade is well worth it in my opinion. However it may depend on what speakers you are driving. Also have you retubed your 150 amps? If not check out the review at enjoythemusic.com (no affiliation)...buy the tubes he recommends and it will be the best $xxx you've spent...huge difference.
Therefore I got the upgrade from Rogue without getting the tube change that is part of their upgrade...my tube change was better than the factory. However the KT90's are really nice. These were factor replaced...The articulation improved and control is outstanding. The two improvements that are right upfront are an increase in weight to instruments on the soundscape...each becomes more believeable and fleshed out. Also the soundstage opens up considerably...more air and greater width and depth.
With that said I don't know what your speakers are but I drove Usher Be-718's. I am now running Volent VL-2's. The Ushers were not enjoyable when running the 150 version...these speakers need lots of power. Most of the negative reviews I read I assume are from people under driving them (I've run 4 different high power amps with them)...the 180's on the other hand grabbed a hold of the Ushers and made them sing perfectly! Huge difference. I think this is a result of the speaker needing a little more umph and not that the 150 was flawed in any way. The Volents have only been heard post 180 upgrade. Therefore difficult to say. I think the 180's are certainly giving me more articulation and solidity than the 150's did so I never look back. However if you are driving a highly sensative speaker the Rogue might get too analytical and cool as you increase power output...that was a critisism of the 120 to 150 move a few years back. My belief after many years and many speakers (including Spendor and Merlin) is that the Rogues are not for high sensative speakers and are really the "Tube" amp to drive inefficient speakers.
Either way you go you have great amps. You must retube...maybe take the factory upgrade to 180 and down the road play with rolling per the enjoythemusic suggestions. I just can't stress enough that the tubes are holding back the amp more than you could imagine! Even the guys at Rogue were impressed when they were running them in...I personally picked them back up after 180 upgrade and everyone (all the techs) came over and said the monoblocks never sounded so good.
Good luck...we'll worth it if the rest of your system can reproduce the benefit.
Therefore I got the upgrade from Rogue without getting the tube change that is part of their upgrade...my tube change was better than the factory. However the KT90's are really nice. These were factor replaced...The articulation improved and control is outstanding. The two improvements that are right upfront are an increase in weight to instruments on the soundscape...each becomes more believeable and fleshed out. Also the soundstage opens up considerably...more air and greater width and depth.
With that said I don't know what your speakers are but I drove Usher Be-718's. I am now running Volent VL-2's. The Ushers were not enjoyable when running the 150 version...these speakers need lots of power. Most of the negative reviews I read I assume are from people under driving them (I've run 4 different high power amps with them)...the 180's on the other hand grabbed a hold of the Ushers and made them sing perfectly! Huge difference. I think this is a result of the speaker needing a little more umph and not that the 150 was flawed in any way. The Volents have only been heard post 180 upgrade. Therefore difficult to say. I think the 180's are certainly giving me more articulation and solidity than the 150's did so I never look back. However if you are driving a highly sensative speaker the Rogue might get too analytical and cool as you increase power output...that was a critisism of the 120 to 150 move a few years back. My belief after many years and many speakers (including Spendor and Merlin) is that the Rogues are not for high sensative speakers and are really the "Tube" amp to drive inefficient speakers.
Either way you go you have great amps. You must retube...maybe take the factory upgrade to 180 and down the road play with rolling per the enjoythemusic suggestions. I just can't stress enough that the tubes are holding back the amp more than you could imagine! Even the guys at Rogue were impressed when they were running them in...I personally picked them back up after 180 upgrade and everyone (all the techs) came over and said the monoblocks never sounded so good.
Good luck...we'll worth it if the rest of your system can reproduce the benefit.