I've used Pentax since the mid-1960s (H1a) and Leica since 1968. After retiring I've collected some of the models I couldn't afford through the years. These two Leica's (M5 and Leicaflex SL2) were pretty much the peak of Leitz engineering. Both are their "50 year" anniversary models from 1975, since they marketed the first 35mm camera in 1924-25:
The M5 was an outstanding user RF, with a great spot meter, that raised a small CdS cell just in front of the center of the shutter, and moved it away as the user pressed the shutter. A very selective spot. (The original Pentax Spot-Matic prototype also swung a spot CdS cell just under the focusing screen to measure a central spot as well.) The M5 was a bit larger than the "classic" M models and so users didn't like it, but it deserved better. I use a Voigtlander 50 1.5 Nokton on it which fits the size well.
The SL2 also used a selective spot meter, but a larger spot equal to the microprism area of the finder, with a piggy-back mirror behind the main mirror to direct the light down to the photocell, similar to the Pentax LX mirror structure. The SL2 also used a wonderful match-needle meter, which of course is easy to read in bright light, but also in very dim light as a button push turns on a small backlight for the meter needle. (This was before LEDs, which I find harder to see in bright light.) This has a period-correct 50 Summilux 1.4. The special hood holds any filters, and a small wheel on the side of the hood will rotate a polarizer filter to get the desired effect. The Leicaflex mirrors used a compound linkage to decelerate the mirror to avoid vibration
These are very solid but smooth and precise cameras, and are a joy to use.