ChasoEater: Are the Might And Magic games worth playing today?
Only you can decide that for yourself. Whenever I want to decide if I'll like a game I watch one or more Let's Play videos, which will show off the gameplay, load times, possible UI difficulties and anything else.
Try watching LPs for MM3. If you don't like the gameplay or graphics, jump up to MM6 and watch some LPs for that. If you don't like MM6 either, then skip the series.
ChasoEater: I am new to the series although i play Heroes Of Might And Magic Games often.
As has been said, MM and HOMM are different games. The MMs are CRPGs, while the HOMMs are fantasy strategy. If you like HOMM 3, I recommend the WOG or ERA mods.
There is a storyline that weaves between HOMM 1-3 and MM 6-8.
ChasoEater: The problem is I don't understand where to go or how to attack. The map is very limiting. And it leaves
me totally confused what to to do next.
This is the nature of CRPGs, the ability to explore the world however you want and do whatever you want. More recent CRPGs do a lot more hand-holding with the player, telling you exactly where to go and what to do. Older CRPGs give you quests, but let you decide when to do them and sometimes even how to do them.
If you love to just explore new worlds and poke around, always eager to see what's around the next corner, CRPGs are for you. If you want more linear "do this, go here, now do this" type games, CRPGs might not be for you.
ChasoEater: From the gameplay I have seen so far it looks like a great series of games but
how does one learn to play these games properly?
RTFM
ChasoEater: Another very important question I have: do these games have replay value?
Only you can decide that. The replay value of CRPGs consists of doing the same quests and areas with new parties, or new strategies, or roleplaying differently. There is no new, randomized content.