Indeed... When I got a couple of Gamma 6's, the engineer actually said "those are quite expensive when new" - which suprised me when you consider, as you say, they are prone to damage from vandals - and the optics aren't exactly modern now; a WRTL 2000 can provide better light distribution along a road. The china hat Gamma 6 I got was full of dead insects, and considering the work I had to do to get the canopy to fit and form a seal against particle ingress I think it had never been IP65 rated (despite the label) from the day it was built. Other lanterns like the Vectra have a cable gland in the spigot which can be tightened to for a seal and prevent the good old column spiders from making a home inside the lanterns - but the gamma 6 only has a fine piece of gauze... and this looks fine when the lantern is displayed, but as soon as you push a cable into the lantern this pushes the gauze out of the way and then the spiders can get in!Yeah the Gamma 6 is very poor by modern standards. I was amazed they were still in production until 2003! In the 70s and 80s they were insanely popular. As a kid I even had a 'Mr. Chimney-Pot' toy house which had a model version of one in the garden!
There are still loads of them in Blackpool and all the roads they're on are all quite poorly-lit at night. The Gamma 6 is one of those old-school group B lanterns that lights the area around the column very brightly but then leaves a massive dark patch until you get to the next lantern. The WRTL 2000, as you say, is far superior and I've never yet seen one damaged by vandals despite some being in quite rough areas of town. Is the Gamma Basique really any improvement? I've never been under any at night. They look just like a Gamma 6 with a scarf wrapped around it's neck to me!
The Jet looks like an upside down blimp/airship/barrage balloon, but gives what looks like better optical performance than an Opalo. They must be decent if they can be used on 10m columns running a 57W PL-T lamp and not appear dim! I may get my Jet in the post tomorrow or Thursday, so pics will get uploaded in due time.Neither the Opalo or the Jet have seen any use in my local area yet, which seems strange when you think of how cheap they are.