Acumatica's defining decision is that it does not charge per user. Licensing is based on the computing resources you consume and the applications you switch on, which means the warehouse supervisor, the shop floor lead and the part time bookkeeper can all have logins without a budget conversation. For an organization where far more people need to see ERP data than transact in it, that changes the economics completely.
Where it wins
Distribution, manufacturing, construction and field service are its strongest editions, and they are genuine editions rather than a checkbox. Construction gets AIA billing, retainage and job costing. Manufacturing gets bills of material, production orders and material requirements planning. Distribution gets landed cost and multi warehouse allocation.
The platform is modern in ways older mid market ERPs are not. A real REST API, a proper mobile experience, and a customization framework that survives upgrades rather than trapping you two versions behind, which is the failure mode that strands so many ERP customers.
Pricing is quoted, and it is not per seat
Acumatica publishes no list price. Cost is driven by transaction volume, the applications you licence and your deployment choice, and it is quoted by a partner. Independent estimates put small deployments in the region of several thousand dollars a year before implementation, with implementation itself typically a five figure project, but those are third party figures rather than Acumatica's.
Unlimited users is the headline and consumption is the meter, so a business with high transaction volume and few users can find the model works against it. Model your own volumes before assuming it is cheaper.
Where it frustrates people
The partner relationship is the whole experience, exactly as it is with Sage and Dynamics. Acumatica does not implement its own product, and outcomes vary enormously with who you pick.
The install base is smaller than NetSuite or Dynamics, so finding staff who already know it is harder and the third party add on ecosystem is thinner. Reporting is powerful and takes real learning, and most customers end up with someone internal who owns it.