Yes, there are many benefits to doing showcases and accompanying tuition. But, as with everything else in the industry, there tend to be patterns that can be expected to emerge from showcase work. Firstly, it is extremely unlikely (even with a reputable organisation promoting the showcase, such as Actors Centre or Actors Studio) that any 'top drawer' agents will come to a showcase like this. The blatant truth is that the only time they *ever* choose to set foot outside their doors is when they have been told they can view someone who is already being touted as 'the next best thing'. It is good to have the showcase participants 'vetted' initially, because it sends out a signal to those who might consider attending that those involved are not just wannabes and hopefuls. BUT there is still no reason that major agencies should take the event seriously - and they don't. I recently worked on the Actors Studio course, which had a lot going for it, and we were left, ultimately, to make our own applications to the major companies, casting directors etc. across the board. The course has a good rep, but out of something like 100 top flight invites, not one bothered to show or respond (and moreover these invites were split between the group, and so sent by different people, with differing approaches). At the showcase, there were indeed a smattering of agents, some of whom gave the performers representation. But, surprisingly (?), none had been specifically invited by us (it must be assumed they had responded to news of the showcase's coming up). In truth, it is generally only agents who themselves have need for clients who will turn up at showcases (e.g. those who are starting up a new agency and need to fill the books etc.). There is nothing wrong with being taken on in this scenario, of course, and if you are agentless having an agent suddenly take an interest is wonderful, but actors who have visions of IML dropping everything to come and see them perform in their latest small scale showcase are seriously deluded! Many young actors seem very ready to attack any drama school showcases they may have done, and I sympathise because these are often hastily put together whilst the performer feels unprepared, and don't end up showing the actor off in the best light...but it should be realised that most drama school showcases still have a higher cachet than later showcases you can do outside, and are more likely to attract industry interest.
It is another truism that the actors who are most likely to pick up agents are those who are already distinctive and castable. This does seem to mean a lot of 'ethnic' actors benefit more heavily from showcases of this sort, because most small agents feel there is a paucity of black/asian/mediterranean/etc. actors available to them, but can see very easily the money to be made from filling 'ethnic' casting brackets within the industry. Other actors who are similarly specific - have a very distinct physique, unusual face or delivery, strong accent etc. etc. will also tend to stand out, and may be offered representation on the strength of this. It is *always* more difficult to snare an agent if your 'type' is common within the industry, if only because agents don't possess a 'spare' slot for you to fit into - they never like the idea that they are taking on actors who will duplicate the skills range, style, look etc. of someone else already on the books for a variety of reasons. The irony is, I suppose, that often the actors most eager to do showcases take them on because it is hard for them to find an agent in the first place, but ironically, this is not through lack of talent, but lack of specificity. And, however hard they may work in the showcase, the same result tends to emerge, and for the same reasons. Therefore, you should really be clear on what you want to get out of a showcase course before you embark on one!
For me, doing the Actors Studio course was partly to sharpen up camera skills (they are very screen oriented, although, oddly, the showcase stages in a theatre!) and partly to meet casting directors etc. who would have otherwise remained inaccessible, and learn more about their perspectives on the business. In this respect, the course succeeded admirably. The showcase at the finale was, for me, a kind of added bonus. I *was* offered further representation on the basis of it, but chose to remain with my current agent (that sort of proves my point - I was not an actor who needed agency interest to be generated by the showcase, anyway).
Whatever happens, the golden rule in any showcase is that you have to perform with as much energy, commitment and belief as you can possibly muster. It is this that can make you stand out from everyone else in the showcase who is taking it for granted/ hasn't bothered to prepare their five minutes as if it was their starring role in a three hour Ibsen. So, always take the work seriously.
Finally, on a practical note, Actors Studio courses are expensive (Actors Centre sounds cheaper), and very screen orientated (so only take if you are interested in camera acting). They are no longer being held in Pinewood (or weren't a few months ago), but instead near King's Cross/Islington...which was much more convienient for me to get to, personally!
Hope you can find a showcase course that will help you grow. Feel free to PM if you would like more opinions on the Actors Studio course.
