How long have you had him? I've always warned folks that dogs (and cats) are usually on their best behavior for the first month in a new home. They tend to follow the "if I'm really good and cute, they'll keep me" logic. Then after a month or two (dogs usually can't hold on to good behavior more than 2 months, cats can go up to about 6 months), they decide you're hooked and start showing their true personalities. Because of this and that he's young, his current behavior is subject to change at any time.
You mention "dogs" - are the others in crates also? Or will you be weaning this one off a crate as he grows up? If he will be the only one in a crate, then you should consider the potential for the other dog(s) to mess with the softsided crate (pawing, leaning against so it gets scrunched, etc.).
Another consideration is temperature. Softsided crates can retain heat more than a traditional metal crate. Depending on where you go and how you travel, that could be an advantage or disadvantage.
The last difference I'd mention is that a softsided crate will have less "openness" than a traditional metal crate. Again, that could be an advantage or disadvantage depending on your situation. Having less openness means that the puppy won't be able to see as much of what's going on around him - will that put him more at ease or create stress (how does he feel if you cover his current crate?).
After years of rescue and fostering, I've always used the metal or hard plastic carriers/crates because I know it will be used by more than one animal, so I have to buy for the worst scenario.