Once all of the BDE based components have been converted to IBO based components it may still be necessary to clean up the Uses clause in all of your unit files. If this is not done then it is still possible to have the BDE's code linked into your EXE. Plus, by removing these unit references it can show additional pieces of code that are not yet fully converted over.
Unless you actually test it on a machine without the BDE you may find that your application still requires that the BDE be installed on the client machine if just one reference to a BDE unit is remaining. So, as a precautionary measure, test the EXE on a workstation that does not have the BDE installed. You will of course still need the IB Client installed as a minimum in addition to your EXE.
Begin to explore all aspects of your application and see how the feel of the application has changed. Take note of anything that seems irregular or perhaps even slower than the BDE. In some cases a little additional tuning may be necessary.
By and large you should expect IBO to be much more responsive and fluid in how it interacts with the server.
Pay the closest attention to datasets that are fairly complex and make sure that they are functioning in the expected manner with satisfactory performance. Both for updates, lookups, filtering, locates, finds, etc.