mjr wrote:Flick-knife-style multi tools are only good if you are sure your bike allows such bulky tools access
Agreed, and it all depends on the bike. I suspect the Hexus is Topeak's biggest selling multi-tool, and it's probably designed with the off the shelf bike in mind, i.e. mass market MTBs and road bikes with standard groupsets. On such bikes, it's likely that there will be the access necessary.
Fit mudguards, racks, lights and other aftermarket accessories, or use a hub or fixed gear instead of derailleurs, and that may change and something like the Hexus may longer be a good choice, at least not on its own. I've just had to replace the allen bolt which clamps the rear brake cable on my non-off the shelf, self built MTB with an external hex bolt, because the combination of brake (BB7), disc size and the particular shape/position of the seatstay meant that it was impossible to insert an allen key or even just a hex bit on its own in the original clamp bolt.
Folding multi-tools do have their advantages. You mentioned the Topeak Ratchet Rocket, which is a nice tool, but the short length of the bits means that I cannot use it to tighten the bolt securing my drop bar brake levers (I've just tried it to check - it won't reach the bolt and the extension bar has too large a diameter to allow it to be inserted in the brake). Even an ordinary L shaped allen key is no good: the short arm is not long enough, and using the long arm means having to grip the short arm, which does not provide enough leverage. The allen key on a fold out multi-tool is however perfect for the task, which is why my home toolkit includes a Park folding allen key tool as well as L shaped keys and a mini-ratchet.
Whatever the OP's needs or preferences, I think the Topeak Survival Box which the OP is considering is just not a good set of tools, and moreover is poor value for money at the £27.99 price in the Evans link. For that price you could buy a Hexus (£12.99), a Park MT1 (£9.99
) which has short length allen keys to complement the long length of the Hexus' keys and 8mm, 9mm and 10mm external hex wrenches, plus a Spokey (£4.50