I agree with nartac for the most part but have some info to add.
The radiator:
I have what I believe to be the same exact rad only a few years older....I still use it.
It does not perform as well as a Chevette heater core but it does do pretty well: my "seat of the pants" observations lead me to believe that it is almost as good.
The pump and block alone are not much less than the cost of that kit, and they are definitely good units.
I would think that kit is a pretty good way to start if you want to get a sure-fire decent water cooling setup as your introduction to water cooling. (Note that I started my H2O hobby with a Swiftech kit- h202c a few years back.)
But I do still agree that a few changes can improve the system- mainly the substitution of a better=performing radiator (chevette core or a larger single pass one.)
That is a good kit though, in my opinion. Swiftech stuff is good.
(That kit is about $50 less than I paid for mine too!)
Edit-
You posted while I was composing.
The system I use my slim Swifty rad in is an mATX rig that just could NOT fit a heater core, period- not enough depth in the case to cram one in. If I could fit one, I would.
The Swifty rad actually takes up almost the same amount of case surface as a dual fan heater core; less width but more length than a Chevette core. It can be....tricky to find a good spot for it just like a heater core.
The advantage it has is that is is not DEEP: with the included fans it will only take up about 1 1/2" of room. Most heater cores are 2" deep, not counting fans and shrouds. The compromise is really that you get a rad that is slimmer than most but doesn't cool quite as well.