As the owner of the previous wireless mechanical keyboard from Logitech G613, I have to say that this keyboard is a significant improvement. I have had it for about 2 months and I am completely satisfied.
Among the positives, I definitely include the switch change. The Romer-G mechanical switches that the G613 had were flawed and over time led to key chattering (registering a command multiple times with one press). The new switches on the G915 are the new GL tactile low profile switches (a special form of Kalih choc switches in reality), they are much more pleasant to type on and considerably quieter compared to other mechanical keyboards I have tried.
The keyboard seems to be quite sturdy as the base and the entire back are made of aluminum. It has a beautiful design with a brushed finish. On the back, there are 2 stands for adjusting the tilt when placed on a desk. The RGB lighting is very impressive and fully customizable through Logitech's G-hub with 4 levels of brightness. I was pleasantly surprised by the battery life, as with heavy use (10-12 hours a day, with 8 hours purely typing), it easily lasts 3-4 weeks, but at a low lighting level. The wireless connection is extremely stable and very fast, as I have not experienced any disconnections or delays. Additionally, its range is very satisfactory as I have it in the living room, about 5-6 meters away from the PC, using the wireless lightspeed connection, and I have not had any issues.
Now, about the keyboard. On the top left, the "G" that marks the series also changes color according to the selected effect. On the left, there are 5 programmable G-keys for storing shortcuts. On top, there are four M-keys, with M1, M2, and M3 used to expand the G-keys. Essentially, for each M-key, there is a set of five G-keys for storing up to 15 shortcuts in total. The MR-key is used for recording macros. Above and to the right of the M-keys, there are 4 additional buttons. The first and second are for switching between lightspeed and Bluetooth connections, respectively. Overall, the keyboard supports 2 wireless connections (one via the USB dongle and one via Bluetooth) and one higher priority wired connection (as long as the cable is connected). Next, the third button activates game mode, and the fourth adjusts the RGB brightness. In the upper right part of the keyboard, there is another set of four buttons for media control, and just above them, there is a very convenient scroll wheel for adjusting the volume.
Now, onto the negatives. If you spend a lot of time on the keyboard, it may tire you out because it does not have a wrist rest, although its height is very low, and I'm not sure if adding one would make sense. The keyboard lacks indicators for Num Lock (unacceptable) and Scroll Lock, as well as a mute button. The keycaps on top of the switches do not seem very durable, so removing them must be done with special care. When the Bluetooth connection is selected, it could support more than one device, as we see in many other keyboards. Lastly, its hefty price makes it almost prohibitive.
In conclusion, if you are an enthusiastic gamer and at the same time spend a lot of time typing and want to control 2 devices wirelessly for quick switching between them, then perhaps you belong to the category to whom this product is addressed.