I probably am, that is kind of why I'm asking for more practical results.
Catching Assault Transports is my main goal to work out how to best accomplish specifically.
I've never felt a need to run those down rather than pincer them.
(Note that in addition to the 'full pincer' where you send two adequate fleets, I believe there's a 'sacrifice pincer' you can pull off where you make sure you know which fleet will arrive first, and make that one a disposable escort or similar. Invasion fleets may still flee from it. Fleets that fight it will probably still be stunned so the main group can force them to action.)
"Good" here is with an * that you need to spend thousands of units of water for propellant, and another that the dV isn't good even then. Which is part of why I wish I had the catch formula. The Fission Lantern, Flare Drive, and Firestar Drive all can get really high cruise values for heavy loads, but they only get a couple hundred dV at best and take a lot of propellant to do so.
The other Gas Core all get dV the same as Advanced Pulsar or better, but with twice the thrust in many cases, which while not great is at least an alternative there.
The main benefit I see is the chance of Salt Water if you have good fissile income, and being able to go straight to antimatter from Gas Core.
I generally look at the delta-V of Advanced Pulsar and Pegasus as merely adequate for local defense ships. Even with slush tankage I generally didn't put more than ~20 kps on them, and often down around 12 before that! I may have an unhealthy unwillingness to spend reaction mass liberally, though I can't say I feel bad about it. You can make interplanetary transits with them if you really want to, but I am never willing to spend the kind of resources it would take to move fleets that way so I don't build the capacity in (beyond very optimal on-phase transfers, which are sometimes achievable for my local-defense ships).
So the idea of making any kind of substantive intercepts with those exhaust velocities isn't something I've ever given serious consideration.
Part of my commentary was less that fusion isn't good, and more that I am trying to work out the use case for many of the drives. I'm just getting to them, and the calculations are making me wonder if on another game I might try to just get Gas Core and only worry about the fusion tech needed for base upgrades (Which is just "In Space" and "TeraWatt", which both don't need the really expensive "fusion method" techs).
Well, from my perspective as a z-pinch fusion user:
My early fusion drive, Triton Pulse, didn't get much use. Partly for economic/historical reasons - I didn't have a lot of spare MC in its time and didn't want to scrap and replace my older types - and partly because with my sparing approach to reaction mass it didn't really open the solar system up. I built targeting 60 kps, which makes many interplanetary transits possible but most of them still too slow to want to use much. It might have been good if I needed to do interplanetary inner system warfare to liberate Earth orbit or something, but I never did. The combat thrust was also decidedly weak, due to the low multiplier. I have a handful of ships from that generation still around, but they're largely just joined to fission-based local defense groups. I didn't stop building Pegasus Drive local defense warships at that point, because they were cheaper and better except for missions that never really happened. Due to the fissile component in the reaction mass, they didn't even feel cheaper to operate.
The Zeta Helion/Z-pinch III ship generation is interesting. They're expensive and massive and don't have quite as much combat thrust as I'd prefer. But I built them with enough delta-V to show up the aliens - targeting at least 1000 KPS on most, which is honestly quite low for the exhaust velocity they offer. They have no problem blasting from Mercury to Jupiter on a direct line, spend negligible fuel on local intercepts, and do have viable options of intercepting alien fleets passing by towards the inner system. Cruise thrust isn't high, but since none of my earlier atomic rocket designs had enough delta-V for that to really matter I don't feel the lack. They also have terrible turn performance due to the massive power system and the inability to scale up rotational thrust, though I'm not sure I noticed that as a problem in combat.
Zeta Helion/Flow Stabilized Z-pinch is pretty much cheating. The drive cost drops to almost nothing, and the radiators become a lot less massive as well. These can easily reach or exceed my usual target for combat thrust (1 g) even on dreadnoughts. I could build nothing but this for the rest of the game and probably not have any problems. If you stack them up you could even get pretty significant cruise thrust, though other technologies that rely less on the combat multiplier probably can do better.
Zeta Boron is an interesting side path. I developed it late and got the flow stabilization so I'm not sure I need it. But it does achieve significantly more thrust - and draw less power, which helps even with the exotic reactor but would be hugely beneficial if you were limited to Z-pinch III. It has a great deal less exhaust velocity than the Zeta Helion, but still vastly higher than any of my other combat drives. I have a few 'local defense' oriented designs that use it and have a few hundred KPS - more than the budget for my early electric drive colony ships, certainly plenty for inner system interplanetary moves and well capable of longer hauls if not as fast. You could certainly achieve more than that if you were willing to load them down with more reaction mass, I'm not sure where the balance between more thrust and more mass would fall if you didn't mind piling that on.
I spent a loong time waiting for fusion drive research to happen, having inadvertantly avoided pretty much all its precursor technologies early on (except to some extent the fusion pile prereqs).
