I own both a Thermal Arc as you describe and a Ranger 250 as the smaller lighter machines that I use in the engine driven variety. I do not weld pipe other than pipe columns which does not really count in the usage I understand you are choosing. I have used the Thermal more as a really good generator as the power output is extremely clean as compared to the vintage of Ranger 250 I own. It was also very useful in AC tig welding of aluminum in the field when portable work was encountered. However, the architecture and the electronics of this machine are by no means comparable to the Ranger 250 for use in more extreme enviroments. The open portions of the machine around the engine are problematic in inclement weather and when it snows then you have got a real problem as the governor linkage for the Honda engine, as used in this powerplant, freezes up quite easily. Not when running mind you but rather in transport to the job. Mine stays covered continually as a result of this problem. The Thermal Arc is quieter than the Lincoln in direct comparison at welding loads. But the overall ease of use is much better with the Lincoln by far. I have run multiple air cooled Miller welding powerplants and for some reason at the elevation we work at they do not do as well as either the Lincoln or the Thermal Arc. Both the Lincoln and the Thermal arc are very smooth when using FCAW process in the field. But the fact that the welding current control is more of direct throttle positioner on the Thermal ARC machine is a major bummer as you are required to continually adjust the amperage/throttle control up and down while switching between welding and grinding. If you do not adjust the throttle up then the grinder runs at reduced power which is annoying. IMHO if Lincoln would build a fully featured machine like the Ranger 250 and 305 with AC output option like their GXT model and it was as clean in auxillary generating power as the Thermal Arc; they would corner the market for a versatile air cooled light weight machine. The architecture and the electronics such as wiring connections, switches, etc are just that good on the Lincoln. The enclosed case is awesome for extreme enviroments and the Kohler engine is no disadvantage to the Honda in actual practice. Funny now that I think about it my Ranger 250 will be six years old next month and it still as the original battery in it.
While a bit more money for sure, I would say if your primary requirement is DC welding power and auxillary generator use for grinders and the like (not sophisticated electronics) then the Lincoln Ranger 250 would very tough to beat. Oh yeh! despite what the brochures say, my Lincoln V-205 TIG machine will not run at or near max output in AC Tig welding mode when powered by the Ranger 250. I even went so far as to test it again on a brand new Ranger 250 in the same welding conditions. Same result. Apparently the power output on the auxillary generator side of the machine is not clean enough for the Lincoln V-205 inverter. A bit of a bummer for sure at least in my work. Hope this helps you!