Like others here, I have had OM slrs since 1975. I love them.
The OM-1 has a great meter. Compensation is easy to set for backlit or high contrast scenes. You just have to use your head a little. But it all feels very natural and quick.
If batteries are a concern, you can use hearing aid batteries but I would recommend an adapter or conversion.
Also be careful putting a heavy flash unit on an OM-1 or OM-2 since they can crack your valuable accessory shoe. The Olympus T-20 is a great flash and light enough with only 2 batteries inside.
Just for confusion, there are also the OM2-sp and OM-PC (OM-40) that have a full program mode. (setting both shutter and aperture automatically). And the OM-PC has the ESP matrix metering which is great for slides.