The comments have already been made regarding the TTL and sTTL considerations here. The S95 w/o a hotshoe is simply better served by an optical cable and sTTL.
Bulkiness for me is an issue not just travelling but even when doing Macro as the smaller rigs can fit into tighter surroundings to achieve better shooting angles and composition. In the case of the S95. The size of the ike housing is not as bulky and clumsy as the G series ike housings. So not that big an issue I think.
What has not been discussed is the system of lenses and accessroies that each housing is able to support.
The ike housing with 67mm (built-in) is practically the same price as the canon with and Inon LD adapter. So what you really have to look at I think is what you want to achieve with the set-up and the lenses available to do it.
I think the Macro lenses for either set-up is about equal.
For Wide angle, I think the Inon LD allows the UWL10028LD plus dome will provide you with the widest available lens arrangement without any compromise. This to me would be the deal maker in favor of the canon housing.
INON Attachment Lnes [Lineup]
INON Mount Base [Overview]
On the strobes - I prefer Inon and Sea n Sea over the ike DS-51 only because I would be considering the canon or other housings in the future and optical is my preferred connection for greater flexibility when upgrading to another camera/housing set-up in the future.
Having mentioned my preferences - I must say that I have had ikelite products as far back as 1989 and their reputation for after sales and service are absolutely the best in the industry. If their products fit exactly what your needs indicate then they would be the choice to go with. One of the SB members Dhaas has tons of experience with the ikelite products and the photographs to back it up.
The camera in this digital age is ''future trash'' so put more emphasis on the selection of lenses, strobes and arms that fit your requirements now and the future. Then choose a housing/camera to drop into all of that.
The most important thing is to put the camera/housing/lenses/strobe to use and start taking lots of photos.