I think that the lc-a would be a better choice if you can find one "cheaper" than what the Lomographic society is asking for this.
As mentionned in this thread the lc-a is not really a toy camera, I use it mostly with b/w films now and I really enjoy the result.
I looked at the holga 135 but didn't felt interested because it doesn't look really like "a small holga". The particular rendition of the holga comes from its plastic lens that hardly covers the 6x6 format, there is strong vignetting and blur on corners. Transposed to 24x36, the lens is "too good", they has to put a filter or something like that behind the lense to get vignetting ! The rendition is not the same as the original holga.
You should also consider that the fixed exposition is a strong limitation, you can live with it with a 12 shots roll on the holga 120, but with a 36 shots roll it can be more annoying.