pros = looks nice, aluminum case, fan
cons = expensive ($96
), reliability issues
, external power supply
deciding factors against = the expense and reliability issues
pros = fan, internal power supply, price ($57
cons = plastic case
(which is a minus by itself, but this particular case appears to be a little flimsier than others and, IMO is ugly), poor USB performance
deciding factors against = plastic case, usb performance
*All tests I have seen show USB doing worse than Firewire, but this particular one showed a more dramatic degradation with USB. Now, it might have been that the degradation was due to the tester's computer/USB chipset/drivers and not the enclosure, so I didn't weight this factor 100% when making my decision, but I did give it some consideration.
Plumax IDE USB 2.0 & FireWire 1394
pros = fan, internal power supply, price ($56
cons = plastic case, lack of information (e.g. couldn't find manufacturer's web site)
deciding factor against = lack of information
ADS Tech DLX185
pros = quiet fan, metal case, good-looking
cons = external power supply, expensive ($87+
deciding factor against = expense
CompuCable FireXpress 525DX
pros = fan, metal case
cons = fan on side rather than back, probably reducing effectiveness since air must make right angle turn to get out of case, proprietary external power supply
deciding factor against = proprietary external powersupply
*Most external power supplies provide a single voltage of +12 V through a standard barrel connector, and thus could be easily replaced with a generic supply if they failed. The Compucable supply, however, supplies both +12 V and +5 V through a 3-pin DIN connector, so it would be harder to replace if it failed.
pros = aluminum case, fan, looks nice, moderate price ($67
cons = external power supply
deciding factors for = aluminum case and fan for a moderate price
After having purchased, tested, and returned the Coolmax unit, I have to make the following warning: Don't buy Coolmax enclosures.
They don't work as advertised. Despite claims to the contrary, the enclosures don't support large hard disk drives on the Firewire interface. Additionally, Coolmax's customer and technical support is completely non-existent. They simply ignore all attempts to contact them.
These are, of course, based on my own criteria and others' would differ. For example, I put external power suppies on the con side, beause I feel that they are an extra hassle to cart about and more likely to fail (e.g. cord breaks) than an internal supply. On the other hand, they are easily replaced if they fail, and, as Inertia rightfully pointed out, they have other advantages as well. Thus, others might view external suppies as a plus. And opinions about what cases look good and what look ugly are purely personal preferences.
I haven't yet placed my order, so if you see something that I have missed or disagree with my evaluation, let me know! It might help me make a better decision.
By the way, the runners-up in my evaluation were the Bytecc ME-320U2F and the CompuCable FireXpress 525DX.
<edit>fixed broken links</edit>