Had this Kona Honky Tonk for a number of years. It was set up as a low maintenance cheap road bike with downtube shifters, sora 9s drivetrain, trp brake levers. I was very happy with how it worked, but tried a few modern (gravel) bikes lately and thinking of going with integrated sti levers. Have two questions:
1. Are current Sora STI levers any good?
2. Anybody still use downtube shifters and like them?

1. Yes
2. Probably
I've put the 3x9 Sora's on my tourer. I have Shimano STI's on other bikes everything from 105 to DA and whilst Sora may not be as posh, they do the job just as effectively. Too soon to tell for longevity but I can't see any reason why they shouldn't last just as well.
I've also bought a spare pair for future proofing
Yes to both.
I love downtube shifters , i find them relaxing to use for riding my bike so much so that the ultegra 11speed bike got punted in a four of an old steel roadbike. Whats more i like them frictionless.
The ultegras were great, i totally get why STIs exist and if i was doing more serious road riding or had to do alot of traffic heavy routes i'd get them gain.
My gravel bike has bar end shifters. I like them even more.
My gravel bike has STI shifters and I don't think I would mind too much if it had downtube shifters instead. I'd miss them on the road, but generally I think they would match the rest of the bike being "perfectly imperfect" for most rides.
I couldn't go back to dt shifters. Probably from having done a number chain gangs and road races. I can't see any drawbacks but if your riding is very chilled, they might lend themselves to that.
I tried using a downtube shifter for a bit on my (road) commuter and TBH several decades of using bar-mounted shifters just means I found them annoying and faffy.
But I'm also quite into the idea of not using STI type brake/shifter, my own gravel bike is using Gevenalle levers and I have a bodged DIY version now on the commuter, both currently running in friction mode...
Probably from having done a number chain gangs and road races
In both those cases i would absolutely use STIs
I ran Sora 9 speed brifters for years and have been very happy with them. I went to 105 and it wasn't that much of a difference. There's no way on earth I'd go back to having downtube shifters now. It would be like going back to bar top friction shifters on my mountain bike. Not happening.
I see why they can be a bit dangerous in a group ride/race, but I always ride alone and I'm a slow rider. The feedback on Sora STI looks to be positive so will try them for a while and see if I like them.
If I ever use gears again I would go for down tube shifters as I am in a bit of old steel bike phase and as I don't race or group ride I just prefer in keeping with the period of the bike.
Yes being able to change gears more quickly is an advantage but so would having gears.
I used DA bar end shifters on my tourer ( which were lovely),but when I started to do more gravelly stuff the shifters got in the way a bit ,so I changed to STI. I did look at those convertors that turn bar ends in to old style ' Thumbies ',still might do that at some point.
Yes, I did a retro criterium race in Belgium on my old bike with DT shifters - it was a bit hairy at times trying to find a gear whilst bumping over cobbles.
Friction shifters are pretty reliable and it's easy to grab a wodge of shifts in one go - providing you can reach them easily. You also need to adjust the cable tension less frequently when they're in friction mode. STI is really easy to use from the hoods or drops, which is ace for racing, riding in groups or riding in traffic. Shifting while braking is doable, and that's not the case with downtube shifters unless you have prehensile kneecaps.
Also have a look at the Gevanalle option if you want a middle road that mixes the simplicity of downtube or thumb shifters with a bit of the convenience of STIs; you should also be able to re-use your downtube shifters.
I have used 9 speed Sora for a few years and always think how crisp it shifts every time I ride my old CdF. I also have a lovely old 1980’s road bike with down tube shifters and although I love them, they remind me of riding my 10speed Raleigh Arena as a kid and a certain nostalgic feeling. I wouldn’t ever consider putting them on a modern bike. Modern integrated shifters are a much better idea.