Most remote burner liquid fueled stoves fall into two categories: 1) valve at the pump only or 2) valve in-line in the fuel line (some stoves in category 2 also have a valve at the pump)

CATEGORY ONE
Take a look at an XGK.

There's no valve on the fuel line. The valve is part of the pump. Since there is no valve to block or impede the fuel line, a cable can be run down the fuel line. The cable can then be pushed and pulled back and forth to scour the fuel line to remove "lacquer" and carbon deposits. For these purposes, I'm considering the pre-heat loop/generator to be part of the fuel line.

CATEGORY TWO
Now, take a look at an Omnifuel.

There is a valve in-line in the fuel line. This valve is what gives the Omnifuel it's wonderful simmering capability (and why the XGK doesn't really simmer). Now, please show me a valve that can both shut off the fuel and have a cable running through it. I don't believe that a cable can be run through a valve. My Omnifuel doesn't have a cable, and I doubt that any Omnifuel does.

I have four liquid fueled stoves that I would consider category two stoves: an MSR Firefly, an MSR Dragonfly, an Optimus Nova, and a Primus Omnifuel. All have the in-line valve; all simmer wonderfully; none have a cable down the fuel line.

My contention, based on my knowledge of how stoves operate and my personal experience is that category two stoves are not as reliable as category one stoves. I'm not saying that it's like night and day, but in general the simpler category one type stoves will require less maintenance and have fewer problems over time.

As in much of life, you are faced with a trade off: the ability to easily simmer on demand is fabulous, but in choosing simmering you give up some reliability. For a "bug out" stove, I'll take reliability and choose foods accordingly.

HJ