Every multichannel retailer reaches the same fork in the road. Buy one platform that tries to do everything, or buy the best tool for each job and connect them. The question sounds technical, but it is really a question about your team, your margin and how much integration pain you can absorb. After nine years of watching both approaches in UK retail, I can tell you the honest answer is rarely the one the vendors want you to hear.
What the two architectures actually are
A single platform ERP runs finance, stock, purchasing, orders and often the web store or point of sale on one database. One stock record, one order record, one set of master data. Best of breed means a specialist ecommerce platform, a specialist warehouse system, a specialist finance package and a middleware layer moving data between them. Both are legitimate. They fail in different ways.
Single platform projects fail when the retailer discovers the platform's web store cannot match the specialist one they are replacing, or when the warehouse module is a decade behind the standalone WMS they already use. Best of breed projects fail more quietly: the integrations degrade, the sync breaks at 11pm on a Sunday and nobody owns the gap between systems. Disconnected systems are usually best of breed architectures that stopped being maintained.
Where the single platform wins
The single platform's advantage is not features, it is integrity. When shop, web and marketplace orders all touch the same stock record, you do not need reconciliation. The margin report is the same numbers the warehouse sees. There is no argument about which system is right, because there is one system.
That matters more as channels multiply. The online retail index published by IMRG tracks how much of UK retail demand shifts between channels, and retailers on single platforms adjust to those shifts with configuration, not new integration projects. If your answer to "where do we sell" changes every year, a single stock record is worth more than any specialist feature.
There is also a staffing argument. A single platform means one team to hire, one training programme and one support contract. In the current UK market, where experienced retail IT staff are hard to find, that simplicity has a real cash value. The Retail Gazette covers the constant reshuffling of retail technology teams, and most of that churn lands on whoever maintains the glue between systems.
Where best of breed wins
Best of breed wins when one function is the business. A retailer whose entire model depends on warehouse throughput should not accept a platform WMS that does 80% of the job. A fashion business whose online store is the brand should not downgrade to a platform's storefront. In those cases the specialist tool pays for its own integration.
The other case is where you already own a strong specialist system. Replacing a working WMS or a working ecommerce platform to achieve architectural purity is almost never the right trade. I have seen retailers rip out a perfectly good warehouse system because the new ERP "needed to own everything", then spend eighteen months rebuilding features the old system had delivered for a decade.
The integration reality nobody prices
When you compare quotes, the best of breed option looks cheaper. The integration work is buried in the project plan as "connectors" and "API development", and it is always underestimated. Every marketplace, every carrier, every payment provider is an integration with a lifecycle. APIs change, endpoints get deprecated, and someone has to notice.
The real cost of best of breed is not the build, it is the running. In the marketplace integration walkthrough I break down what that maintenance actually involves. For a retailer with a small IT team, three connected systems can consume the whole team's capacity just keeping the connections alive.
A decision framework for UK retailers
Use this three step test rather than a features spreadsheet:
1. Is one specialist function the reason customers buy from you?
If yes, that function is non negotiable and should stay specialist. Everything else can live in the platform. If no, the platform approach removes more risk than it adds.
2. Can the platform's weak module be worked around?
Ask for a proof of concept on the two or three functions your team rates weakest. Workarounds are cheaper than integrations if they are honest workarounds, not denial.
3. Who will maintain the seams for five years?
Name the person. If you cannot name someone whose job includes keeping every integration healthy, you cannot afford best of breed. That is not an insult, it is arithmetic.
When the answer changes
The framework points most retailers toward a single platform, but two situations flip it. Fast growing retailers adding channels every quarter should avoid locking a rigid platform into processes that will change again next year; the build versus buy analysis covers that case. And retailers whose margin depends on warehouse efficiency should keep the WMS, as explored in our comparison of ERP and WMS.
Whichever way you go, the ten questions still apply, because the worst outcome is not choosing the wrong architecture. It is choosing the right architecture and the wrong vendor. And if you are mid project and the seams are already showing, the common omnichannel ERP mistakes article explains where to look first.