In no particular order here goes.
There are a few versions of this tyre, some of which have no wired beading and are in black. There is also a newer version which has the rather good looking tanned sidewalls. The version I have are the wire bead type.
These are your racing tyre and weigh in at 176g a piece. I regard then as summer tyres that look wonderful and even better with the mudguards off. They are also quick and the narrow diameter lowers your gearing by 2.5%. I used them at the Brompton World Championships and Nocturne races and loved them. Do they actually make you faster on paper? Possibly not. Did I feel I was able too ride faster with them fitted? Definitely...especially when pumped up to the maximum 115 psi!!
If there is a downside it is that they do tend to be more puncture prone due to the thinner construction. I know a few people who use Kojaks exclusively all year round. One is a Londoner with the tanned sidewall version on his Chpt3. The other is a Canadian who uses his on his all back S2L Superlight cycling in Calgary.
This is the tyre that comes as standard on all new Brompton bikes unless you pay a little more for something else.
These have a good tread and weigh in at 255g a piece. I have to say that I really like the Racer. It is a great tyre that offers a fair amount of puncture protection. For me they are a great summer tyre and I would tend too use them over the Kojak for that extra puncture resistance.
Many of my Brompton friends swear by the Marathon Plus when riding in and around London. They offer the best puncture resistance of any of the Brompton tyres (there is one other option I'll mention later). So if you do not want to be bothered as much by the puncture fairy, they might be for you too. They weigh in at 480g a piece but can be pumped to 110 psi.
With earlier versions I seemed to have a recurring issue where the tyre came away at the beading. The newer versions don't seem to have that issue. If there is a negative it is that they can be hard to fit back on if you have a puncture but that extra peace of mind is worth it for many a Brompton rider.
The Marathon sits in-between the Racer and the Plus in terms of puncture resistance and is one of the upgrade options when buying a new Brompton.
Weighing in at 420g they can be pumped up to 110 psi and offer a very good amount of puncture resistance.
As far as rolling resistance (here we go) for me they feel faster and less sluggish than the Plus. Many of those boring tyres I mentioned would get a spreadsheet out and argue differently.
There is a tyre by Tannus that has no inner tube at all but I am told that they are not a pleasant experience to ride.
Tyre giants Continental have a tyre for the Brompton call the Contact Urban. Probably similar to the Racer I have yet to give them a go but hope to do so soon.
Stay safe out there people!!