So far, playing SMT 1 and 2, they're a lot easier than Nocturne. Demons don't level up, which is useful because they start off with all of their skills. There's something weird going on with buffs too, I was able to use Tarukaja something like 8 times for godly attack power.
You'll get lost a lot, though. The map isn't exactly easy to access and the menus are sluggish and often unresponsive. Most of the music you'll hear while just walking around will be boring and repetitive (in the first, second has great town/dungeon music), with the exception of the Ginza theme, which is bloody amazing. It's not a battle theme, but I'm embedding it here regardless.
Also, you'll have to use a guide. It's one of those older RPGs which never tells you where to go or what to do, and it's not common sense either. There's also a glitch (in the first) with the translation in the Law route, or so I hear. But hey, nobody ever sides with Law in SMT games, anyway.
If you still want to go ahead and give them a shot, start with the second. It lacks a lot of the problems the first has and will help with the transition into the first if you still intend to play it. If you haven't played Strange Journey, also play that before 2. It'll help to ease you in even more.
I'd say they're still worth playing, just for more SMT.