Hanley, I just received my X-T4, and I can tell you, it's a wonderful piece of equipment. I upgraded from an X-T2, but had considered the X-T3 with the recent price drop.
My decision to upgrade was based on the following:
• The advanced face and eye-detection for the AF (I've shot with an X-T30, and it is noticeably better than the X-T2, however, it is not weather sealed and I enjoy street photography on a rainy day).
• I was one of the Fuji shooters who really wished I had better battery life. Although, it made me hesitant to pull the trigger. I have six of the NP-126s batteries, now I will have to start building a reserve of the larger battery.
• I had a tough time deciding between the X-T3 and X-T4, it's the same sensor and processor - so for 90% of the images I take, it will be the same photo, and I do not shoot video. However, I do like to shoot street photography at night, so I am hopeful the IBIS will help with sharper images (can't wait until quarantine is lifted so I can shoot).
• Between the X-T3 and X-T4 I also liked that the shutter on the new camera has been redesigned and is (reportedly) much more durable. I shoot a lot of local sports for work - and those bursts can rack up a lot of shutter actuations. The longer shutter life was a major plus for me.
In short - if I already had an X-T3, I likely would not have upgraded just for the IBIS. However, since I was on the X-T2 and looking for a new body, the X-T4 had some key features (longer battery, more durable shutter, and AF) that I really did want.
I hope that helps!
