Friend asked why I bought SWF shares. Answered in elevator pitch., page-4

Positives:
Strong organic (word of mouth) growth. The growth almost runs on auto-pilot.
Becoming profitable now.
At ~6% market share, but taking 25%+ of new and swapping traders, so trending in the direction of 25%+ market share.
Lots of options for increasing revenue per user, eg. adding services, improving subscription, up-selling IPOs etc.
Large scale can give them more options for reducing brokerage costs - renegotiating or going in-house etc, or partnership with OM.
Possibility of takeover. (Since it's a quick way for a larger company to get a high market share, then be able to promote their own services.) Eg. Bell Financial own their own retain brokerage, wholesale brokerage and financial services. They probably won't want 2 retail brokerages, but say they didn't have one, then they could easily take it over to get the market share and be able to promote their other financial services.

Neutral:
They still have lots of room for improvement (endless feature requests by customers), but they've reached this point anyway. They'll be improved over time.

Negatives:
Big brokers cutting costs is a fairly big risk to their growth. (IG already cut, but IG not being CHESS sponsored makes them not as much of a risk as say Commsec)