In general, when you are looking for web hosting service, the location of the server, may it be in UK or US or any other place in the world, it hardly matter as long as your country has no objections. However, when it comes to colocation, the location of the web server plays vital role in managing and maintaining it.
Before going further let us try to understand what is colocation and the difference between the other. When a customer wants to own the web server to store his or her website data and wants to operate one server independently, they purchase the web server outright from the hosting company. The server would be still located in the data center of web hosting company itself in the racks of the datacenters of the web hosting company. So, web host customers, generally with good technical and web hosting knowledge prefer this to save the charges for hosting services. So what the customer pays for is the web server, power supply and bandwidth. And of course it is a personal preference too.
Like VPS hosting, colocation also comes with managed and unmanaged options. The managed colocation leaves the responsibility of maintaining the web server to the web hosting professionals. Any updates, modifications are performed by the web professionals on the request of the customer.
On the other hand, unmanaged colocation services provide only the physical space and racks for the web server to be placed in datacenter. The customer is completely responsible to handle the server, with necessary updates, management, modifications and also upgrades.
Managed colocation anyways is managed by the company itself, so not to worry about the location, however for unmanaged colocation the location of the datacenter of the company matters a lot. The physical maintenance of the server demands you to be at the location of the server for better maintenance. Before you sign up, the server and its surroundings of the data center demand your presence. You need to see the physical conditions of the servers.
For managed or unmanaged colocation anyways demands very tidy interior of the data centers with many factors coming into the picture. The temperature of the server room must not exceed 72 degrees Fahrenheit along with the allowed humidity to be 45%.
The physical parameters like how the server is placed and dust and cooling conditions with necessary isolation of the servers are to be very carefully considered. The servers must be placed with a reasonable distance apart, at least for an aisle length to comfortable movement if required. This keeps the servers to flow air in between. It makes the server to function properly, when the server rooms are made with dust proof, without allowing any dust inside.
Finally it is a good choice to go for colocation, provided if the location is closer to you. At the same time it needs proficient knowledge about hosting and every petty thing about web hosting. That makes you paying only for the server, bandwidth and power supply only saving great amount of budget on the services.