Well worth it IMO but it doesn't come with a filter in that setup (I think). If I could do it over, I'd look into the fluval C2 or aquaclear 20. I just bought the spec V and although cool looking, the light is built for low light plants.
You're right, no filter for the 89.99 package.
I do like the aquaclears. I've had a few of them over the years, and I'm running one right now on my main tank. The C2 interests me, but I've heard that the flow is quite heavy - one review I saw said the C2 set on "low" had more flow than an AC set wide open. Do you have it? Is it too much for a 4gallon?
I'd even consider a small canister if I could control the flow and block the intake properly to protect fry/shrimplets.