Only thing that annoys me so far is that items like titanite shards are "hard" to get since the blacksmith only have like 20 on him (dont remember but not much) so if you find a wep and upgrade it only to find a better later on and you dont have enough shards to make it +3. You can find the blacksmiths daughter that will sell you as much shards and large as you want, but you meet her pretty late in the game....(i am SL90 atm about 17 hours still havent found her or damn shards 
)
as for pvp i have only been invaded 2 times myself but they both fell of some cliff. And summoning is super fast i often put it down and get message 3-10 seconds later no more 10 min waiting 
i imagine it being about the same speed for invaders. And you can put your summon sign pretty much anywhere so if you want you can do a whole area with a friend or other ppl
I don't want to tell you but there are EASY ways to acquire all titanite up until Slabs (I only have gotten 3 so far) but there are infinite Shards, Chunks.
As for PvP and summoning: Summoning is almost instant which is fucking awesome, I can co-op regularly if I wanted too. Brotherhood of Blood (a.k.a Darkwraiths) can get cracked red eye orbs from dueling each other in a arena then using the orbs to invade areas (invade are easy to get into though I've never personally been invaded). The blue cracked orbs can be used to invade Sinners and those are slighty harder to get into due to not many sinners and not many Dark Wraiths yet but if you spam the orbs youll get in it. The convenant can also come to the defense of any Way of the Blue convenant members that get invaded but that shit rarely happens since there are not a lot of invaders yet and even less people in the blue convenant. Then you also got the Rat Convenant which I have not tried but apparently you can set up traps and if someone walks over it they get summoned into your world where you try to defeat them and prevent them from getting to your rat king. I briefly tried it and had zero fucking idea what was going on until I read up on it. Last one I've tried is the Bell Tower which in my opinion is the most fun, basically what you do is equip a ring and the ring will summon you to people who are trying to ring the bell tower and you gotta kill them and stop them. Pretty much PvP matches every 1 minute or quicker and a bunch of fun.
P.S - The Sunbros still exist.
