It all depends on what you're looking for; if you want a genuine Hofner sound without spending thousands, I recommend going with the Hofner CT. It's virtually identical, sonically and physically, and if you're a geek/stickler (like I am), you can easily affect the cosmetic changes to make it look like the German model.
The Hofner Icon (now called the Ignition) is something I'd honestly have difficulty recommending over a Jay Turser or Rogue (or any of the plethora of knockoffs out there). The Icons seem to be a bit ~too~ much on the cheap side; their switches seem very fragile, as someone pointed out in an earlier comment, and it's just flat out not as well made as the CT.
So, if you've just gotta have a Hofner, skip the disappointment, save up, shell out and get the CT.
Regarding the Epiphone Viola, I had a 1st Gen model once upon a time, and I genuinely regret ever getting rid of it. I haven't had an opportunity to check out these latest models, but I've got the bug again, so I hope they're still made as well as they were back in the late '90s. If you're looking for a violin-shaped bass to evoke the visual nostalgia, but with a bit more versatility, the Viola is the way to go. I've heard about the Brice and and the Anderson (and, again, a plethora of brands), but I assume they're all still made by Samick (or at least they're all probably made in the same factory and rebranded for the seller). Regardless of the 'brand', you're most likely to still get some really decent boom for your buck.
As has been mentioned, the Viola is a tad more stout (and larger) than the CT, so that may be something for you to consider. However, if you're normally a solid-body player, the weight difference(s) will be noticeable to the positive side, whichever one you choose.
One last thing about the violin basses; they can be uncomfortable to play, depending upon your arm positioning. The sharp edges of both the CT and the Viola can cut off circulation to your forearm within the span of one song if you're not careful. I suggest trying out one of each for a substantial amount of time to see if you're comfortable playing on it.
So, if you want the authenticity at a bargain price, get the Hofner CT.
If you want a nostalgic-looking bass that's more versatile, you can't go wrong with the Epiphone Viola.