Junyo line is less popular due to longer grinds. Also the first CV comes in at 60. Which is higher than the Hosho line. The CVs in the Junyo line are a little better, but not overwhelmingly better. This is why you see so many IJN CVs from the Hosho line.

Taiho and Shokaku line are pretty niffty looking though. Taiho looks like an aparment buidling lol.

I was planning to use this line until I realised I couldn't sell my gunners (yellow name) to fund the carrier so I gave up.

I worked out the Junyo line, although longer grinds, means you spend much less money overall buying new ships and you lose less money because none of them have remodels. I was hoping to do it just to be different, rather than any genuine reason of the ships being better, but I do think they look pretty sweet.

there are couple of players using junyo line in kaiser, but most player pick hosho line because of fast transistion from each tier or early cv at lvl 40? or more plane space than the other line but all will end up in 1 shinano

oh forgot 1, hosho line get more cv to choose (including the remods)

I DID have Junyou, but I hated Taihou so much I reset the B.O.to Akagi and continued on THAT line...got a Kaga now...
Taihou is a bucket. I utterly hated it. The grind was insane, the ship itself got about 19 knots, and the AA guns weren't great.

I can understand the AA problem and fighters what good are they if they get shot down even when they outnumber the enemy fighters.

Went Hosho line and got a BO reset... so i got the Taiho.
Taiho aircraft wise is better than Akagi and it's remod but falls short of Kaga.
The gun placement is terrible (especially compared to kaga) so if you like guns i'd advise against it...
Oh and it's one of the better armored CVs out there... and that would be it.

It's not terrible bit i think Kaga is just better.

On a sidenote.
The CV5 from that line is one of the best in the game when it comes to dodging bombs... it also comes 2 levels earlier than most.

I have both lines and have found that the Junyo line is better. The Taiho is great at dodging bombs and shells even with no engys on it. I never use AA on my CV cause I carry ftrs. The thing with ftrs is that you shouldn't concern yourself with how many enemy ftrs you can shoot down. If your ftrs are lower lvls, you need to either try to drag enemy ftrs, scout for your BB's, or look for bomber waves or scouts to kill. I can get 15K in shoot downs with a loss and get 18K XP. Or I can get 7K in shoot downs and 30K XP with a win. So try to help your BB's as much as possible.

As far as the main differences in the 2 lines.

Hosho line has more CV's which breaks up the grind nicely. And most CV's in this line are slightly better than the Junyo line when is come to DP and being able to launch more planes at earlier lvls. The exception to this is the Taiho. Compare the CV 3's and the Taiho is better until you get the Kaga. But you will get the CV5 2 lvls earlier in the Junyo line than the Hosho line. The Junyo line, even though it has less DP, does seem to have better armor than the Hosho line too.

Im currently 86 sitting in taiho, the grinds are not bad and the ships arent bad, personally i think junyo line looks sexier, especially the cv2 and cv4 :)