The learning that derives from building your own can't be matched by buying a complete pistol, and it also can't be valued with a dollar value. My first build probably cost me $50 or $75 more than I would have spent for a new Rock Island pistol with a lifetime warranty, but I think the knowledge I gained from the process was easily worth a lot more than $50 or $75.
The nice things about using a lower cost kit for your first build is that you don't feel like committing Hara Kiri if you mess up something due to lack of knowledge. Plus you don't worry of you decide to change something. My first kit had a GI grip safety and a GI-style hammer. It functioned fine, but I finally decided I wanted a beavertail. I didn't feel confident enough to start grinding away at the receiver, so I bought a Wilson Combat drop-in. Then, of course, the GI hammer wouldn't work with the beavertail, so I had to buy a hammer.
One other point: I like Caspian products very much, but they are unfinished ("in the white"). The Armscor slides and barrels from Sarco are pre-finished. Sarco offers both a "GI" slide and a "Commercial" slide. The GI-style has small-ish, GI-type sights. The 'Commercial" slide has more contemporary, slanted cocking serrations and greatly nicer sights.
