No pumps. The relative costs depends on the relative price of gas vs. electricity so I don't think any answer will be universal.
I have gas hot water radiators in my house. However, it is zoned and I don't heat the upstairs where we sleep. If the temperatures upstairs start dropping into the 30's I'll turn on oil filled electric radiators in our two bedrooms rather than heating the whole upstairs. Doesn't seem to drive up the bill excessively, although we typically only use them under those circumstances for a few hours a night.
My boiler is slightly undersized for my house. (I bought it used cheap) so when it get to about 20 below zero it has to work hard to keep the house in the mid 60's. I considered installing a higher BTU boiler but concluded it wasn't worth the effort. For the few days every few years where it gets that cold. oil filled electric radiators are an adequate supplement.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13