What feat do you think it works best for Concentration saves and casters in general ? 
the ability to cast S components spells while your hands are full are lovely but if you are holding a spell focus cant you use the M components instead of the S anyway ?
the ability to hit an opportunity attack with a spell is also great but ... HOW MANY TIMES is somehow gonna escape the melee range of a caster ??? 

what do you prefer the advantage for con save or adding your prof in con saves ?

Quote from HaLwAsA >>

 HOW MANY TIMES is somehow gonna escape the melee range of a caster ??? 

well I am playing a dragonborn druid :D .
so I am really carious what would be more helpful .

well its says this 

. A spellcaster must have a hand free to access a spell's material components -- or to hold a spellcasting focus -- but it can be the same hand that he or she uses to perform somatic components.

it says this in a clear separate paragraph for the spells in general after the paragraph of material components . because other wise ti will be very stupid for a caster to keep don and dof his focus to cast a cantrip or S only spells . like for a druid who have a shield .

again twitter is not a source for me even if Gygax himself was tweeting himself .
if WotC want something to be canon post it in the companion . and when I looked I did see this lovely disaster XD .

If the same cleric casts cure wounds, she needs to put the mace or the shield (her material components) away, because that spell doesn’t have a material component but does have a somatic component. She’s going to need a free hand to make the spell’s gestures. If she had the War Caster feat, she could ignore this restriction.
(SAC 1.14 , page 12)

welp .... this is not cool XD .
all these spells ... geee :\ 
its not enough that some spells make no sense sometimes . specially Flame Blade  I need a free hand and material components to use a blade made of fire ...... its dump its either on or the other !

This really depends on the kind of damage that your pc is taking each round. I know some DMs increase monster damage instead of monster hit points to deal with needing to make encounters more challenging. In that case it's hard to make a con check either way. (apparently Mearls surveys aren't very broad to have noticed this would be a problem). 

Early on you are better off with Advantage, which is like a +5 bonus. As the game progresses you probably wont to get both unless it wouldn't make a difference. 

It's a silly rule that only makes sense if you don't have a focus in your hand. The idea being you can make the gesture and then reach and grab the material component.... But how can you make the gestures with a focus with one spell... But suddenly can't make a gesture with another spell just because it doesn't have a material requirement? 

And besides how many players actually keep track of those things to begin with. 

Honestly I'd just rule you can cast any spell while holding a focus since if you can make one set of semantic gestures while holding it, you can make another. 

  Until a goblin goes... Look shiney magic weapon! 

Seriously though I don't know why more DMs don't have monsters pick up players weapons. 

If the intent is to gesture with the materials... I. E. Hold the diamond out, etc. sure. But the rules don't explicitly state that. 

The only thing that annoys me is RAW only "Holy Symbols" get to be Emblems on shields.

it doesnt have to be . it can be a totem or a necklace . it just have to be a symbol of your god Visible to all and when casting a M components you have to handle it  

Quote from HaLwAsA >>

again twitter is not a source for me even if Gygax himself was tweeting himself .
if WotC want something to be canon post it in the companion . and when I looked I did see this lovely disaster XD .

If the same cleric casts cure wounds, she needs to put the mace or the shield (her material components) away, because that spell doesn’t have a material component but does have a somatic component. She’s going to need a free hand to make the spell’s gestures. If she had the War Caster feat, she could ignore this restriction.
(SAC 1.14 , page 12)

 

welp .... this is not cool XD .
all these spells ... geee :\ 
its not enough that some spells make no sense sometimes . specially Flame Blade  I need a free hand and material components to use a blade made of fire ...... its dump its either on or the other !

1) but you need a hand to use the material components so no shield .
2) its concentration ... for a spell that used to create a melee weapon .
3) the most useful times to use this spell and [Tooltip Not Found] is when you are without any equipment and both of them ask you for material components .... just genius . and when does the druid can uses all their spells without and S , V or M components ... at level 20 . yaaaaaaay .

other stuff that make me sad for the druids .
1) not enough lighting spells .
2) the attack cantrips are sad .... attack rolls cantrips have 30 ft range .... really sad :( .

Why would you want to use an attack roll spell over another spell anyway? Besides wanting to roll dice? 

There are cantrip attacks that have a longer range than 30ft. and are more likely to hit than your attack rolls. 

If you don't have equipment you cantrip attacks are going to be way better to use anyway. 

Also ice knife requires water. Water is required for life. So chances are you are going to get water at some point. 

(unless those evil drove are going to keep giving you tea so the evil dm can keep preventing you from doing that) 

yes A single spell fabuless I will have to keep spitting then ....

and I dont know I am at the sewers now looking a bunch of rats  .... who wants to eat me after I tried to talk to them . 

we will see today is the day :\

Your captives are going to give you something to drink. You don't have to spit.