K-line product was very good for it's time compared to the price. Certain pieces stick out for me as being superior such as the H-24-66, the Superliner cars most out of the 21" production line, and the EP-5. Their EP-5 is the most "scale" out of nearly everyone ever done in O and is more accurate than Overland's brass version from some years ago.
I like their F40's as they replicate the "Phase II" production variant from EMD with the recessed fans. While not always accurate for the paint schemes they put on them, that is what distinguishes theirs from the MTH production.
Overall a great product line that was balanced at a good price. However, regardless of the lawsuit, I don't know if it would have been sustainable in today's market. The market has just changed so much.
My "graffiti" version of the SP express boxcar is a one of a kind I believe. I purchased this out of Gordon Wilson's collection at a TCA Desert Division Auction a number of years ago when he was thinning out his massive collection.