All small cc street bikes are made with cheap materials compared to their higher cc lineups. This doesn't apply to all small cc bikes since there are high quality dirt bikes and such that only need to be small displacement. This really only applies to small cc streetbikes.

This isn't to say they aren't reliable however there's far more of an assurance that their higher cc lineup will have higher grade materials which will result in less degredation in parts that will need to be replaced over time. The bigger issue with smaller cc street bikes is that that there aren't that many people in the states that want to keep them for long-term usage which is why you'll see a ton of them in the marketplace. They generally run the **** out of them in a short timeframe and then upgrade. When you buy these bikes used then you'll never really know what you're getting till after you've owned it for awhile. Then you'll start to see what the previous owner did and didn't do to the bike. I've personally purchased mine new from the dealer because I am the small few in the states that actually plan on keeping the bike. This does assure me that I'm the original owner since Oct 2022 who didn't run it to the ground and because of that I've gotten so far 9.3k miles in 2.5 years with zero issues. I also do all of the work myself even removing the engine to do the valve clearance. You will pay a ton more new compared to used for that assurance. It's not worth it with a small cc unless you are seriously wanting to keep the bike.

There are a ton of guides online to show you what to look for when buying a used bike.

 

Here is my experience.... I bought a NEW 2016 KTM RC390 (in 2016). I owned it for a year, and put nearly 2K track miles on it. I kept hearing about all kinds on horror stories, blown head gaskets, etc. I kind of felt like the build quality wasn't really on par with its Japanese competition. I sold it, and considered myself lucky that I didn't have any ANY mechanical problems

I replaced it with a Yamaha R3. The build quality was a little better, but it still felt "cheap" (to me). The R3 was super reliable. I actually ended up with TWO Yamaha R3's- one for the street, and one for the track. The motor has stood the test of time (the MT-03 uses the same motor). My only complaint was that it didn't really excite me? It seemed kind "vanilla"/boring to me?

I ended up buying a new 2024 Duke 390, and a used 2019 Duke 390 for my wife. I can tell you that the build quality has improved since 2016, but still on the "cheap" side... The important thing is that the Duke EXCITES me!!! It's more fun than the Yamaha was. I do all my own maintenance. If I end up wrenching on the KTM more than the Yamaha, that's a trade off that I'm willing to make. I currently own three bikes (the others are bigger bikes), and I think my Duke 390 is my favorite bike I own .

 

Big thing to note is that the 2024 Gen 3 is a whole different breed of 390. Virtually everything on that bike is new where you will get extremely limited support if needed especially anything internal with the engine. You'll mostly find Gen 1 support online but they at least relate with Gen 2 compared to anything with Gen 3. Infact, the Adventure 390, RC390, Husqvarna 401 support videos and forums are more related with Duke Gen 1 through late model Gen 2 compared to Gen 3. This will probably not change with Gen 3 for a very long time since the internet is still currently flooded with Duke Gen 1 support all across the globe even though those bikes came out in 2013-2016 which was a good 10y ago.

Also, there are very few parts shared with the Gen 3's compared to the prior gens whereas Gen 1 all the way to the late model Gen 2's have lots of shared parts with each other.

 

I have a 16 390 Duke & it has had its share of issues, which only gave me an excuse to make it nearly 50hp to the wheel after I fixed the issues & tuned it... ;-) As mentioned above, the newer ones seem to have fixed a lot of the issues (not all) that it's predecessor (1st gen) had...

My girl had a CB500F, that was a really nice bike with very smooth power delivery & has Honda's reliability reputation to stand on, although it is kind of heavy compared to the Duke & Yamaha... Have not ridden a MT03 or R3 for that matter, but I would not shy away from one at the right price, since I have an older 07 R6 track bike that I LOVE...

 

Well my ownership experience has been stellar. 19000km, 5 years not a single problem to report. 2020 390 duke. I have a Coober ecu and airbox lid filter and full exhaust. Have run 14.15.16 tooth sprockets for different riding experiences and it absolutely rocks. My nephew went from a restricted MT07 a duke after riding mine and far preferred the duke, much more fun and more nimble. I can’t eat it highly enough. The mods really wake it up as well if you want more down the road, so to speak..

 

Did he get a chance to ride the mt07 unrestricted?

 

i'm on my 3rd Duke 390 - never had any problems .....

Of the 3 bikes you're considering, the MT 03 and the CB500F are "vanilla" bikes, whereas the Duke 390 is a Ben and Jerry's chocko mint chip (with Strawberry sauce) kinda bike ....

When you watch the press reviews of the Duke 390 - The word "special" comes up a lot as does "riot to ride" - you won't get such comments about the MT03 or CB500F (or the Kawa Z400 for that matter)....

Good luck !