"Lightweight" is possibly a relative term; what one photographer considers lightweight another might consider impossibly heavy. A lot depends on usage...
One tripod I would consider given you mention landscape is the Benbo Trekker (Benbo NOT Benro). For landscape use, the advantages are the very flexible leg arrangement (which some describe as wresting with an octopus, as one catch releases all legs to flop everywhere) and the unusual way that the legs slide in; most tripods collapse the legs inside the upper sections, letting any grit, sand and water enter to cause binding. Benbo tripods collapse the legs into the lower sections, meaning that you can stand then in muddy water and not have to worry when it comes time to pack away - provided the water doesn't come over the bottom section.
I've got a couple of Benbo tripods as well as a Manfrotto carbon fibre and a Gitzo so I haven't any particular axe to grind.