The box is pretty collector friendly. There aren't any twisties and everything goes back in pretty easily if you wanted to display it in the packaging. However, it'd be sad to leave Fenrir and Cloud in the box as these are toys that you have to feel in your hand.
Once you have the bike out of the box, the first thing you'll notice is the weight. Fenrir is a heavyweight. The construction is nice and solid, and the material feels durable. There are actual working, rubber wheels front and back, as well as a nice front assembly that give the suggestion of a working steering mechanism. Notice that I said "suggestion", because the steering doesn't actually work. I compared it to my 12" Ghost Rider's Flame Cycle, and Fenrir wins handsdown; Ghosty's ride is sort of a hollow shell with paint apps doing most of the work, while Fenrir is a nice scale model with sculpted parts.
Even if there weren't a Fenrir, you'd still want to get the Advent Children Cloud. Like most of the Play Arts FF figures, he's got a nice balance between sculpt and articulation. While you won't be entering him in any Marvel Legends gymnastics competitions, the re-design of the character is represented well with this figure. His hair is one thing that is remarkable; it's made of a flexible translucent plastic that is very nice. His costume is also great; well sculpted to hide most of the joins, and the apron/overall thing he wears is a separate piece that you can move behind him when he is riding Fenrir.
He also comes with the Buster Sword and and extra hand. The sword is nice, but you're unlikely to ever use the extra hand since it's a b*tch to remove and you'll want him with the sword anyway. You'll want to keep the sword in his hand as much as possible because it's hard to get it out and tends to damage the fingers' paint.
If your familiar with the Play Arts line, then you already know the pros and cons of their figure construction. Joints that become loose relatively quickly, pegs that tend to break off, and plastic that gets dirty fast. The Cloud figure shares all that. Mine already has loose ankle and elbow joints, and collects dust like nobody's business. I would have liked it if they had included a breakaway sword that could be hidden in Fenrir like the movie, but that's probably asking too much.
When the Game Version of Cloud came out with Hardy Daytona, I went through the same thing. This time though I had enough extra cash to buy it at the regular price. Again, the box is the same as the first boxset, with a plastic mold to keep everything in place and a window to view the figure. The set includes the bike, the figure, a few extra hands (again you'll probably never use them since you'll display him with the sword or on the bike) a damaged version of the Buster Sword and some pegs that go into his back where you can hang it.
The pegs are a nice touch, though I don't know why they needed to make it a seperate piece from the figure. I tends to fall out and get lost if your not careful. The costume is no where near as detailed as the first one, and his hair is solid yellow unlike the nice plastic of the AC version. I don't really care much for the figure. What drew me to the FFVII AC line was the relatively realistic sculpts. The Game Versions have that annoyingly cutesy anime look. Many people will disagree, but to coin a phrase, big cutesy eyes detract from the "badassery".
The knee joints on this Cloud are a little weird. Unlike the AC Cloud, the GV Cloud can bend his knees back to about a 65-75 degrees from vertical. The actual joint is hidden well by the sculpted folds in his pants, and allows him to almost sit on his haunches. It's a nice touch, but not necessary since 45 degrees is enough to set him on the bike.
On the other hand. Daytona Hardy is a great toy. Again, there is a great amount of detail in the sculpt of the bike, with individual components showing. There is a rudimentary steering system, but it only turns the front wheel about 5 degrees. Barely noticeable. It stands a bit higher than Fenrir, but it's much much more steam punk industrial. It would go great with any figure actually. If I had to choose, I'd have picked this bike over Fenrir, for the more intricate detailing and general look.
Overall, I'd say the Fenrir boxset is the must have between the two due to the superior figure giving you more value. However, if you're a fan of the game, a steam punk fanatic, or just like really cool toys, I'd say pick up Daytona Hardy as well.