I don't know for sure but the Lowes ad you reference looks the same as the Lincoln SP-175T except you get extra wire and a cheap helmet-like thing in the Lowes package.
The difference of the Plus vs. non-plus seems to be the Plus has continuous voltage control vs. stepped on the T. Look at the technical link on the Lincoln pages for a bit more info about the difference.
That's my opinion after looking at the ads. I don't have any of these.
I have an SP-170T which is an older version of the Pro MIG 175 and I checked parts listings some time ago and found that the SP-170T, SP-175T, MIGPak 15 and WeldPak 155 all used identical parts except for the sticker on the front panel. I'm fairly certain that the Home Depot and Lowes versions are also the same but I haven't checked to be sure.
They use different names because Lowes and Home Depot both offer to meet or beat other prices but only on the identical item. By having them with different names/models they don't have to do that. :-/
I've never checked on the + model because there would be so many differences internally but I'm fairly sure they use the same torch, etc.
The difference between the + and all of the other models is that the + has continuously variable voltage while the T and other versions have a 4 or 5 position switch to select different taps off of the transformer.
The following comments are my opinion only:
The pros of the + version are better control over the weld. The minuses are more complex circuitry which means more to fail and more expensive to repair. Also, for the new user it might be more confusing to try and tune it when you have two variables to adjust, the 2nd being wire feed speed.
The pros of the T and Lowes and Home Depot models is simplicity, meaning less to fail and cheaper to repair, and less confusing to adjust. You simply pick your voltage setting based on metal thickness and wire diameter and then adjust your wire feed speed to get a smooth weld.
As for quality, I've had the SP-170T for, IIRC 3 or 4 years now. I bought it used at an auction for $375. I use it for occasional projects but my son uses it a lot. He's built a dozen or so heavy custom truck bumpers, usually out of 3/16" plate with lots of continuous welds plus a couple of trailers and several other projects. He even did one bumper out of stainless. He pays no attention to duty cycle or preventative maintenance and generally breaks lots of my tools but he has yet to hurt the welder.
Once I went to use it and nothing happened when I pulled the trigger. I reseated the connector for the switch and it's been working fine ever since. That's the only problem I ever had with it and it was an old model when I got it.
Best Regards, Keith Marshall email@example.com
The drive roller/ housing is different along with the drive gearbox on the Plus model. The plus model is more money but is the best in-class. The T or Lowe/HD are fine but for the extra $$$ the plus is worth it. It's super reliable in any form, but for dialing it in perfect, the plus has a edge. It has a better low-end arc then my Miller passport. :)
According to my local supplier, the lincoln version and the lowes HD are the same machine.
HD and Lowes gets a huge volume discount from lincoln. and they have to call it a different name i.e. pro mig;
Can you imagine if LOwes would call it Lincoln SP 175T ot 175 + and sell it in their big box store for 3/4 of the price of what the local welding supplier charge or what lincon charges to their direct customers?
Also those machines; all come out of the same factory lines with a different name sticker. It would not cost effective for lincoln to use a separate assembely line just for lowes or HD to make a lesser quality machine.
Spoke to Lincoln today . . . The Lincoln Electric SP-175T / Pro "whatever, is the same at Lowes & Home Depot as that sold at the welding supply houses. The Lincoln Electric SP-175 Plus is not available in a retail outlet like Lowes, Home Depot, etc . . . I priced the Lincoln Electric SP-175 Plus today at a Reddy-Arc welding supply and they were less than any internet price . .