I do find some mirrorless interchangeable camera uncomfortable to work with over long periods of time. The desire on the part of the manufacturers to get them as small as possible often produces a mismatch between body and lens. One solution to this is a battery grip, with the bonus that I get more power, but I don't always want to use one of those either.
I've had great success with the PhotoMadd grips for my Fuji X cameras. And the grip for my X-T1 is never off the camera as it improves the handling significantly. As you can see above, I've now got a metal L-Plate grip for my Sony A7 FE cameras. The A7's have a decent handgrip already, so this is left out from the one I bought. However, the additional depth and width gives the camera a whole different feel, with a much more comfortable hand grip for me and a sense of stability with lenses fitted. It also adds a metallic feel to the somewhat cheap plastic like finish of the A7 bodies and aesthetically it matches the black steel, 'industrial' look of the FE lenses. I like it very much and I may well get one for my other FE body.
However I won't be getting it from the same place that I got this one from on ebay. zhangbaobao2013 is an ebay company in China, that pretends it's sending stuff from the UK. It's not. When you order something, they order it from the far east, stick a UK label on it and send it out (My package is covered in Chinese customs documentation, which is a bit of a giveaway!). Consequently it took weeks to arrive. I've already reported them to ebay, because this is just a scam. Now there are companies who import from the far east as well, but they only advertise the goods when they are actually in the UK, so when they send the stuff out it's very quick to arrive. So if you fancy one of these grips, I'd be very careful where you order from, if you live in the UK.
However, despite all that it is a good grip and you can get them from a variety of sources. It's particularly useful if you are using some of the larger Sony or Zeiss lenses and it's also very good with large 3rd. party lenses, including some of my Nikons. I really do like L-Plate grips and they add a real solid feel to the cameras I have them for. With any luck Matthew at PhotoMadd might extend his range of products beyond Fuji, since it would be great to have a source for this stuff in the UK.