The Sähköautomiehet podcast has an episode from December 2021 about Plugit:
Just listened to it, highlights:
- “most of the staff are IT people building Plugit Cloud”
- focus has been on AC charging and housing cooperatives; “more legwork is done on the AC side”; a large part of the initial discussion concerns housing cooperatives, not relevant
- “we use hardware and components that can be used far into the future” … “so that we don’t get married to a hardware manufacturer or even a supplier” … “our selection includes brands like Keba, Schneider Electric, Ensto, ABB”
- on dynamic load balancing: “it’s actually our own product, our own technology, our own software”
- Hube (around time 25:15 – 29:20). “Plugit’s own project and product in practice” … “DC / HPC product, 350 kW and that range” … “A portable and customizable fast-charging product”
- Heavy traffic (33:50 ->) HSL, Leppävaara, bus charging. “A charging solution was delivered” … “The high-power charging equipment is there, and then there’s our back-end service used to monitor, measure, and operate the entire arrangement” … “Are there other heavy traffic sites coming? we are investing heavily; we also have an R&D team as a core part of the business, and the logistics side in particular is something we will definitely invest in.”
Interesting case. This was recorded around the time of Kempower’s listing. At least back then, Plugit clearly wasn’t a charger manufacturer, though they were a charger supplier.
But on the software side, load balancing, and back-end services, they are operating in the same areas as Kempower.
It doesn’t really look like that. At least so far, I haven’t found any indications that they are currently a Kempower customer. And based on the podcast, the Viinikka truck charger news + the information in this thread, it doesn’t sound like they would start buying from Kempower anytime soon in the future either, when they can supply their own Hube product. 
But I can’t say how serious of a competitor they are. I would love to hear thoughts from those more familiar with Kempower’s competitors and competitive advantages. 