Amps are a bit more work than pedals - for one thing lead dress (the way you place the wiring, the way you ground the amp) is critical to getting an amp which doesn't oscillate, hum or make strange noises. But it's not impossible. The first amp I ever built was a 5E3 and it sounded pretty good. Now when I make a 5E3 it sounds a lot better though because I learnt from that first one and every one since.
I would probably recommend a 5E3 as a first build. I built a couple of tweed Champs and never really bonded with them. The main thing with a 5E3 is learning how to bias it properly - it makes a huge difference. And it's a bit of a head scratcher at first but you have this place to help. Most of the time people build a cathode biased amp according to the 1959 schematic and if you do it will most likely sound like mush when you turn the volume past 3. Wall voltages are higher these days than in 1959 so the B+ will be higher. I would highly recommend using a slightly lower B+ PT from MM to help make your amps sound more authentic. But if you don't want to you can still get a great sounding 5E3 by using a higher value bias resistor. You want around 100% plate dissipation for a cathode biased amp. It's not that hard to get dialled in with a DMM and a few values in 5-10W resistors.
One of the best sounding amps I have built is the 5F11 Tweed Vibrolux, and it's not much harder than a 5E3. The amp I play most right now is a Brown Deluxe 6G3. Fabulous tremolo and a big fat sound. I like it way more than any BF Fender I've played. Takes my pedals well.