I use a 3M/Speedglas unit. The part number in Canada is CA16-0905-SGXX. It is a complete hard hat/clear visor unit with a PAPR.
I use it for much the same work as you described and for my application, it works pefectly.
I use it for SMAW, GMAW, FCAW, GTAW and CAC-A. My primary use is Mild Steel and Stainless Steel. Once and a while Aluminum.
Seldom do I work on "Clean" material - I repair rental equipment that is contaminated with products from oil and gas well drilling and completions. With the add-on filters, I have a much better margin of safety against all the materials that the wash bay guys fail to remove from the asset before I work on it.
The unit I use is HEAVY and most would find it uncomfortable - Especially guys with long thin necks.
Despite the weight, I wouldn't give up having the clean air, and the wide field of vision of the grinding lens with the welding lens in the raised position.
Should your application require it, the helmet I listed above can be either converted to, or ordered as a unit that works with an oil-less compressor for supplied as as opposed to the PAPR.
If weight is an issue, or the hard had is not needed, I would suggest you take a look at the new 9100FX Air.
http://solutions.3m.com/wps/portal/3M/en_EU/Speedglas/WeldingShields/EyeFaceProtection/9100Shield/Speedglas9100FXAir/If I could do it over again, I would go with the 9100FX Air.
Hope that helps.
Have a good day.