I dig Maris otter, used it for and english barley wine last July.(just now coming into its own)
We did a partigyle, capping the mash with dark roasted grains (chocolate malt maybe?) to make a brown ale from the second runnings. This was one of my favorite beers yet to drink. The character of the base malt really showed through, even in second runnings.
Sweet, carmelish, roasty. The Defiinition of malty.
Would I use it exclusively? Only if I wanted only to brew British styles.
Every malt has its place.