My friend gifted me a Heltec V4 Expansion Kit last month and I ran into a few problems but the overall use experience was great.

That friend also warned me that at that time there wasn't a firmware available for this extension kit with touch screen. I ignored that and flashed the newest available firmware from Heltec's website to the device.

Firmware Problems

It did not start anymore. Confused why the holy drives of Heltec would give me faulty firmware, I flashed the official V4 firmware, which didn't work either, but now at least the Bluetooth version works.

Now, with black screen and a broken will a few weeks pass.

When I finally got the will to live back, I started troubleshooting again.

I figured that maybe the now newest Alpha (v2.7.20) would do the trick and flashed it.

IT FUCKING WORKED.

Later, I found out that I had to flash the firmware from Heltec's website over the V4 firmware at some location that I forgot to remember.

Now, as I am writing this post, I noticed that the flasher for the V4 now includes the MUI. My friend promptly flashed v2.7.15 with MUI onto his V4 Extension Kit and it worked flawless.

TLDR

In the end, everything goes smoothly and you can just flash the firmware without problems.

I was just way too early for the official support of the kit.

Usability

The MUI is as expected. The touchscreen is responsive but a bit finicky at times, though I have the default screen protector still applied.

The 1 W power is great for long ranges, although a bit illegal. The stock antenna is good. My friend tested the SWR and he can't remember the value, but it was under 2.

Sadly, I didn't use the V4 Expansion Kit as much as I would have liked, but I live pretty remote and there aren't any nodes around.

TLDR

The radio is great if you want more power than the T1000-E.

Now, at this time, you also won't have to have firmware issues.