If it's not too late to be helpful...
I just got my copy of "Heroes and Aliens" and I luvs it, I do!
The Heroes part has fully statted character write ups for just about all of the major B5 characters in 2nd edition. Better by far is the fact that each character has multiple write ups, showing how they developed over time.
You get Sheridan, the newly appointed war hero station commander. Later you get Sheridan, leader of the Alliance of light, and down the road you get President Sheridan.
This is insanely useful if you're running a B5 campaign that crosses paths with the canon characters. Now instead of one general description and write up, you can get specifics for whatever point in the series you want to set your game.
Mr. Morden, from minor shadowy enigma to vengeful Agent of Darkness!
Very cool.
The Aliens part, which is the part that I bought it for, doesn't actually have stats for ALL of the Aliens on the map. But pretty much most of the minor ones that matter. I can't wait to do Ipsha or Kor-Lyan characters! I love the Hurr and the Grome! The Cascor are cute! The Dilgar are e-vile!
Lots and lots of updated goodness! (the Lumati finally have differing modifiers for High Caste and Low Caste! yay!)
Most of the write ups are for League races that needed revision for 2e.
(Hooray Markabs!)
There are lots of minor races that I have a specific need for that didn't make it into the book. No Koulani, no Tokati, no Torta/Torata, no Tikar, no Antareans or Golians. No Denethians. ah. But it is hard to complain that wee marginal species that didn't even appear in the show, except in the background, weren't covered when there is so much wonderful cruncy goodness for the ones that did get included.
Did I mention the Ipsha and Kor-Lyans? woot.
For me the real determination of value for buck is: Do these alien write ups make me want to run games featuring the species described?
Big yes!
Could I run a game entirely focussed on the aliens described?
Between this and the Galaxy Guide, I think I could run campaigns set entirely on any of the homeworlds of these aliens, with only characters from these races--and could probably sustain them indefinitely (depending only on the degree of interest my players showed). An all Hurr campaign. Doesn't it just make you wanna?
Give me a race, I'll give you a campaign idea!
Good stuff to work with.
So, money well spent!
That's not even taking into account the Xenologist and thieve's guild prestige classes...
