Yeah, I wasn't sure myself.
I know a fair bit about the Cybermen and I know they can be very dangerous for a few reasons:
01. The newest models were capable of upgrading to new weapons, which would render said weapons useless against them after enough hits; this upgrade been passed to the rest of the units and often meaning the only way to beat them became using a bomb to blow up the planet; this taking out all of the Cybermen at once with no chance of them "upgrading" to counter it.
They could also move at great speed in short bursts and fly: https://www.youtube.com/watch?v=rDYv5z_9SKE
https://www.youtube.com/watch?v=8xCboOM3nSM
02. They were capable of using their "Cybermites" (insect-like drones) to acquire information - which included accessing human technology like mobile phones, repair damaged Cybermen and perform partial/full conversions of humans or other organic matter, with even the Doctor been partially converted and gaining a split personality when the Cybermen tried to turn him into their new Cyber Planner: https://www.youtube.com/watch?v=bbB3MKRpn_s
03. The Cybermen used Dreadnought-class ships known as "Cyberkings" (which looked like 60m tall Cybermen) as the frontline of their invasions; the ships having powerful weaponry and their chest containing a cyber factory that would convert the occupants of the worlds they conquered.
One group of Cybermen - trapped on Earth in the year 1851 - were able to create a simpler version of the Cyberking using the Victorian Era technology: https://www.youtube.com/watch?v=alWMTcQEP_U
However, a true version of the Cyberking would be seen in the comic Supremacy of the Cybermen, where a trio were shown attacking and allowing the Cybermen to conquer Sontar; a planet full of cloned soldiers who the Doctor himself had called "the finest soldiers in the galaxy":
04. The Cybermen have been shown as having their technology be compatible with the technology of other alien species besides humans. In the Doctor Who/Star Trek crossover Assimilation², the Cybermen met and formed an alliance with the Borg.
However, while the Borg couldn't assimilate the Cybermen, the Cybermen could assimilate the Borg - effectively betraying them and stealing their technology to enhance the Cybermen further.
If this group of Cybermen hadn't been stopped, they would have (on the Star Trek side) conquered the Klingons, the Romulans, the Vulcans and even Starfleet Academy.
In the TV episode Doomsday when the Cybermen encountered the Daleks, the Cybermen noted that their species were similar and their technologies were compatible; suggesting an alliance and that "together, we could upgrade the universe": https://www.youtube.com/watch?v=Vxxn4yQUbfQ
(This could potentially be the biggest threat to the Cybertronians - or their best ace - if it turns out that the Cybermen's technology and their own is compatible)
05. The Cybermen are capable of time travel, but it is nowhere near the level of other species like the Time Lords or the Daleks who have mastered it; the Cybermen's version been described as "primitive, limited and dangerous".
Still, I thought it was worth mentioning as the Transformers would later create their own time travel technology in the G1 continuity at least with the Transwarp technology we saw in Beast Wars; G1 Megatron aware that the technology was been developed and leaving instructions for his descendants on the Golden Disc as a result in case he and the Decepticons lost the great war: https://www.youtube.com/watch?v=5Qc5tR_7VXU
Despite all the "gushing" I've just done on the Cybermen, the reason I ultimately chose "Don't Know" as my answer is because I don't have enough knowledge on the Transformers universe.
If this wiki was a shop, I'm essentially the average joe who peeks in, has a quick look around but doesn't delve too deep - compared to some "customers" who would metaphorically stroll in and know most/every detail about everything within (if this comparison makes any sense).
The last thing I want to do is to jump to conclusions without all the facts, as to do so would be an idiotic decision; hence my choice in the poll.
All that said, I think a clash between the Cybermen and the Transformers could be interesting at the very least. I'd like to see the Transformer's reactions to seeing a species that forces organic lifeforms into metal bodies that are identical in more ways than one, while also seeing the Cybermen's reaction to a sentient race of machines and how they may want to "assimilate" elements from the Transformers to upgrade themselves further: https://www.youtube.com/watch?v=sMlUnTF7ekM