There is a fundamental misunderstanding in the discussion, when contributors state (rightly to some extent) that transactions cannot be keyed into the online accounting services, like Xero, Kashflow and Free Agent as quickly as in desktop software, like Sage and QuickBooks. The problem is speed, many say.
If your practice is providing what I would term "binge bookkeeping" services, meaning processing client records in batches, perhaps monthly or quarterly, then there is little benefit from using online accounting systems for 3 reasons:
the client is clearly not interested in maintaining accurate, up to date accounting records, so there is no need for real-time reporting
because the client does not need real-time information, there is less downside in sending backup files to the accountant and back - indeed perhaps the data file is permanently with the accountant, with the client only having financial information provided in the form of reports produced by the accountant, and
data in batches can be entered more quickly using the interface of desktop software compared with web-based software (with the exception of live bank feeds and bank statement upload files)
However, if you wish to provide a management accounting service, in collaboration with your clients, then online is the only way to go. The client would typically enter most of the transactions themselves, in very small numbers but very frequently - i.e. daily. No speed problems here then.
The accountant's role is to monitor, review, correct and complete the records - then use the real-time numbers to help the client manage and grow their business.
Doing the "clever bits", like calculating and posting depreciation or making the stock adjustments at the month end, is high value but low transaction volume work. Again, speed is not therefore an issue.
So my argument is that web-based accounting systems are modern tools to enable delivery of modern services. Accountants can stick to traditional desktop tools if all they want to deliver is a traditional service.