My fiancé and I used IAS and honestly we don't regret using them. But now have gone through this visa process once and having a better understanding and finding this group we don't feel we need a solicitor for the FLR (M).
IAS was great because we had no idea what we were doing and I hadn't found this group before we hired them to represent us so it was worth the money. The only issue we had was lack on communication because our solicitor left the company during our visa process and the solicitor they replaced him with never kept contact or gave us updates or advice. Luckily we didn't have any ill side effects from the transition.
Obviously some people prefer to use a lawyer and that's fine. But the message we're trying to get across is "want" to use a lawyer vs "need" to use a lawyer! The vast majority of our members do not need to use one.
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The second part of the message is, if you choose to use a lawyer, do your due diligence and make sure that they have the relevant experience.
Many are experts at finding ways around the rules for people in complicated situations who otherwise wouldn't qualify, but haven't any idea of how best to put a simple, qualifying application from the USA together!