To start with, the technical differences:
Voyant Adviser can be used on or offline (provided you have set up offline mode on your machine), so you can use it when you are not connected to the internet. It uses Java, so you must have Java installed on your machine, which is why Adviser will not run natively on iPads and other tablets which are not Java-enabled.
AdviserGo is web based, so it will only work when you have an internet connection. AdviserGo has touch screen functionality so is ideal for tablets. It also works on mobile phones (though it would be very small!).
Differences in Usability:
In terms of usability, the two versions are interchangeable, so any clients you create in Adviser can also be viewed in Go and vice versa. Sometimes you might set up a client in AdviserGo, but then go into Adviser to do more detailed planning, e.g., step up or down expenses or withdrawals or income, or do more complex planning, e.g., estate planning.
Adviser allows you to set and amend the liquidation order within a plan, e.g., drawing from pension funds to meet expenses before investments,
Certain products cannot be entered in AdviserGo, e.g., trusts, EIS and VCT schemes - you would need to enter these in Adviser and then open up the plan in Go.
AdviserGo has a more limited range of chart views. It does not include assets by tax type, liquid assets, liquid non-pension assets, or plan worth. It does, however, give you the ability to switch from a bar chart to an interactive pie chart.
AdviserGo has a more limited set of reports than Voyant Adviser. However, the reporting in AdviserGo provides financial overviews and allow for reports from multiple plans/scenarios to be run concurrently.
Certain simulations, i.e., the Monte Carlo and Long Term Care simulation, are not available in AdviserGo. In Go, simulations are called "Insights."
Adviser has a step up/step down feature which can be applied to income, contributions (to savings, pensions, and other investments), account withdrawal limits, growth rates, inflation rates, etc. This is not available in AdviserGo.
AdviserGo has the added functionality of guided "What if" plan creation, taking you through the most common what if scenarios, as well as giving you the ability to create your own scenarios.
AdviserGo has the added functionality of letting you see whether a client is able to meet certain financial goals by entering an expense as a goal and flagging up whether you are able to meet that goal.
AdviserGo incorporates an additional simulation - the retirement spending simulation, which calculates, based on what you already have in the plan, how much the client can actually afford to spend in retirement (as opposed to what they tell you they would like to spend)
In summary, Voyant Adviser is ideal for more complex plans, particularly where you are trying to demonstrate tax efficient retirement income planning, or estate planning, since you have the ability to finesse the way in which withdrawals are taken from different assets. AdviserGo is ideal for building simpler plans, but as the two are interchangeable, you can easily move from one to the other.