Worth purchasing EF 70-200 L USM f4 if already own 18-135 STM?

[GMac11]

As the title says. I have the 18-135 (IS) and it's a great versatile lens but my current penchant is for zoom landscape photography so looking something in the 200mm range. Is it worth spending the money on the 70-200 when I already have up to 135mm covered?
I also want to step up my inventory with an L lens but is the ageing 70-200 really that much better than the modern 18-135?
Any other suggestions welcomed!

 

[GMac11]

Thanks for the replies all, been busy this past week to properly respond. The whole thing is probably moot now anyway. I actually decided to try out the Tamron SP 70-300, picked it up new for £189, it seems to have decent reviews.
Further down the line I may trade in both my 24mm f2.8 prime and 18-135mm and buy the Canon (or equivalent) 24-105 L lens. I have a 10-18mm so I don't think I'd miss the 18-24 too much but it'll be a while off yet anyway.