I have the ViAir 300 portable and it works great on the road for tires, air bags on my TV, etc. I do no think any of the portables would have enough air to blow out lines. I have a full size compressor at home for those types of uses. The portables are great at what they are designed for though. Never leave home without mine.
I have a VIAIR 450P. One of the best purchases I ever made. I recommend VIAIR to anyone looking for a good quality portable unit. It cannot be used to blow out the lines though. You need a compressor with a holding tank for that.
I have a portable, Kobalt 3 gal air compressor from Lowe's. It's 110V that pressurizes up to 155 lbs. and the output pressure can be adjusted down for various applications. I usually blow the lines out by adjusting the pressure down to 30-40 lbs. Haven't had a problem yet blowing apart plumbing fittings.