[5.3 x 4.9 x 2"] Purchased this to have a weather / dust resistant outdoor camera. The smaller size and light weight are a plus.
Have been using it for over a month and enjoy it.

[0.405 lb] As expected, a perfect fit for my OM1, will add some additional handles for video work. Glad to see SmallRig are now supporting the OM Brand.

[0.405 lb] So far all expectations from learning on E-M1 Mark III met. Fun to use. Sturdy.

[5.3 x 4.9 x 2"] Well made. I already had one for my Canon R5 and wanted a matching one for my om-1 travel camera. This one is not full size like the small rig for my R5 but also doesn't add as much weight. Both fit well on their respective camera's and feel solid. They do not block access to the battery or any connector. I did see that some folks are able to use it on their EM-1 MK II but it seems to be a little loose on mine so will just keep it on the OM-1.

[5.3 x 4.9 x 2"] I bought the OM-5 as a smaller, lighter companion to the OM-1. The OM-5 lacks subject detection (birds, mainly, for me), but I plan to use it as an everyday-carry and fun camera that nonetheless has image quality that's about equivalent to that of the OM-1. Not bad. Some people complain about the outdated USB connection and the older Olympus menu system. Yes, USB-C would be faster and more modern. And yes, the menu system of the OM-1 is more intuitive. But I am looking to set up the OM-5 so that it's basically customized to the ways I shoot, and for that its menus are OK. I'm not trying to master every nook and cranny of the camera's capabilities. I have set the camera up to meet my needs for now (as I have the OM-1), and will explore new features when I need to know about them. The OM-5 is a refresh of the Olympus E-M5 iii, which is an excellent camera and is available used at attractive prices. But in the end, even though the OM-5 is just a refresh/update of the E-M5 iii, the OM-5 is a better camera-- better weathersealing, improved processor, hand-held high-res, starry sky AF, etc. You can find other cameras that improve on the OM-5 in some ways. However, it's hard to find another camera this small and light, with IP53 weathersealing, outstanding image stabilization, a huge range of lenses available (new and used), and all in this price range.

[Cage] Still learning all the menu options. Quite happy with the performance so far with the stock 12-45mm f/4 lens (can't beat the price of ~$200 over the body price). Added a 40-150mm f/4 for daytime shots. This 40-150 is a little longer and heavier, but wow, does it open up possibilities for hikes in the mountains. I get home to view the pics and see things I didn't even see when snapping the shot.

[5.3 x 4.9 x 2"] The Smallrig 1/2 camera cage for the OM-1 is great. It fits on my OM Systems OM-1 as well as my older Olympus E-m1 mark II camera. It is fairly low profile. It gives more places to mount accessories like a microphone.

It does raise the camera about 1/2 on the bottom, but it provides a standard Arca style plate for mounting on a tripod. It also extends the camera about 1/4 on the left side, but unless you attach something to the NATO rail, you likely won't notice it. The weight is fairly minimal.

You can completely access the battery compartment without taking off the cage. Similarly, you can articulate the rear screen without issue. The top part does not interfere with the FL-LM3 or larger flashes.

I did notice that access to the two top buttons (AF and sequential shooting) on the OM-1 are a little constrained, but I can still push them. If I used them more often, I might notice it, but I don't use these buttons frequently enough that it would be an issue.

I suspect if you attach and remove the pc-sync cable frequently you might need to remove the cage to take off or put on the cable. I don't use the pc-sync port, so it hasn't been an issue.

The 1/2 cage is not compatible with the HLD-10 battery grip.

One of my interests is to externally power the OM-1 in case I ever need to do long form video like I used to do before the pandemic. With the 1/2 cage, I can mount the Smallrig universal battery holder, and mount some powerbanks that provide at least 27 watts of USB C-PD (power delivery) that the OM-1 wants to provide more power than a standard BLX-1 battery provides. My back of the envelope calculation shows that an OM-1 with a BLX-1 battery and my 20000mAh IDMIX powerbank, that I could perhaps get 11 hours of runtime before having to change batteries.

[Cage] fits great

[5.3 x 4.9 x 2"] I got this for my Olympus E-M1 Mark III. Had heard that the fit is iffy on E-M1 IIs and IIIs since the cage is designed for the OM-1 but it fits well. It is unobtrusive, which is appropriate with a small mirrorless camera like this, and high-quality. As a bonus, it has an Arca-Swiss plate at the bottom for tripod use.

[Cage] Fits like a proverbial well-fitting glove on my OM-1 and supports a SmallRig handle and an external monitor setup well. Doesn't clutter or encumber the right-hand camera grip at all.