Cloak and Dagger or normal Invisibility Watch?

Solution 1:

Having clocked 538.5 hours as Spy, I think I'm well qualified to answer this question.

The Spy has 3 cloaking devices and that all 3 have different uses:

1. Invisibility Watch

The Invisibility Watch (or its cosmetic reskins The Enthusiast's Timepiece / Quäckenbirdt) is the basic, no-frills watch.

Cloak Time

It has the longest cloaking time, but also takes the longest amount of time to recharge if you're not picking up metal boxes.

Knowing the map layout and ammo drops in particular is essential to using this watch.

Decloaking and Detection

This cloaking device uses the standard decloak sound, and can be heard by enemies at close range.

While cloaked, you can be seen as a translucent outline of your current disguise when you are touched by an enemy or take damage.

Cloak restore amount:

• Small Ammo Box: 25%
• Medium Ammo Box: 50%
• Large Ammo Box: 100%
• Dropped Engineer Box: 100%

2. Cloak and Dagger

The Cloak and Dagger only drains cloak when you're moving.

Cloak Time

It has slightly less cloak time than the Invisibility Watch. The Cloak meter is automatically restored over time while you stand still under cloak (or with cloaking turned off).

As of the July 2nd 2015 patch (Gunmettle), the Cloak meter can now be restored by picking up ammo boxes whilst decloaked. Cloak gain from ammo pickup is 35% less when compare with Invis Watch.

Decloaking and Detection

This cloaking device uses the standard decloak sound, and can be heard by enemies at close range.

While cloaked, you can be seen as a translucent outline of your current disguise when you are touched by an enemy or take damage.

Usage

The C&D is the best watch for reporting enemy activity over voice chat and picking off stragglers. Just don't pick off too many, or they'll catch on and start spy checking.

It also pairs well with the Your Eternal Reward knife, as it makes finding a single target to backstab much easier, especially so when you're on RED on a Payload map. If the other team does not watch their backs, you can pick off everyone pushing a cart.

3. Dead Ringer

The dead ringer drops a fake corpse and activates cloak when you take damage.

Cloak Effects

The DR can only be used at 100% cloak meter, and when you decloak, you will have a maximum 40% charge. When activated, you receive 65% damage resistance as well as a speed boost for 3 seconds.

Depending on your current disguise, the corpse it drops is different:

• Enemy team - Drops a fake Spy corpse of your own team color.
• Your team - Drops a fake corpse of your current disguise of your own team color.

Note: As of the April 25, 2016 Patch, the fake corpse is no longer missing a Spy head, making it harder to determine whether a Spy was feigning death.

Decloaking and Detection

This cloaking device uses a loud zapping sound as its decloak sound, and can be heard by enemies at medium range.

While cloaked, your cloak is "perfect" for the first 3 seconds. After that, you can be seen as a translucent outline of your current disguise when you are touched by an enemy or take damage.

Usage

The Dead Ringer is particularly handy if you're BLU on a Payload or Attack/Defend Control Point map to make the enemy waste any sticky traps or Charged Sniper shots.

The DR is exceptionally good to use when pushing carts, as the cart refills your cloak meter very quickly.

Knowing which passages are used less on a map is a huge bonus, such as the inner track on koth_nucleus on the lower level.

Cloak restore amount

• Small Ammo Box: 25%
• Medium Ammo Box: 40%
• Large Ammo Box: 40%
• Dropped Engineer Box: 40%

Note: The 'Saharan Spy' set used to give you silent decloaks with every type of cloaking device, however all 'Item Set bonuses' were removed as of the July 10, 2013 Patch.

Solution 2:

The normal invisible watch is going to be a more versatile watch assuming you know the map. It will refill on ammo pickup and is near-silent when de-cloaking. Assuming you're playing a standard CP or PL map and you goal is to quickly score kills, this is going to be your best tool 90% of the time.

Due to the noise that the Cloak and Dagger makes, you'll need to de-cloak far away from anyone that's paying attention. This pairs really nicely with the ambassador, as you can line up a shot, de-cloak, and go for headshots. It may also come in handy when stalking intelligence in a CTF map. You'll be able to make a move at just the right time and don't need to constantly pick up ammo packs to stay cloaked.

Remember, though - as long as you are hiding and cloaked, you are useless to your team. They're essentially playing a man down. Use stealth to get into position to get your kills, but don't take forever doing it. If you finish a twenty minute round, and you have no deaths, but only seven kills, you're doing it very, very wrong. Way too often the CnD coaxes players into this kind of play style.

Solution 3:

I tend to think that there's a class to play for every situation in TF2. In the case of the spy, I generally switch to that class when two teams are meeting at a certain point and no one is gaining much ground or pushing the other team in reverse.

In this case, I think about which watch to use in terms of how the area between the two teams is organized. This is the area you want to move through the quickest and without being hit by stray fire from the opposing team.

For short spots, such as the bridge in Stage 3 of the Dustbowl, I like the longer cloak time of the normal invis watch because you don't have much of a place to hide. You have to get through a small zone of often intense fire very quickly. You have a little more leverage with the extended time of the invis watch but you should never stop moving.

Spots with more area between two teams, such as the bridge in Double Cross, have lots of nooks and crannies for you to hide in. I'll generally use the C&D for areas like this because you have the opportunity to stop and regen at the beginning, middle or end of this area, depending on the situation.

In any case, don't play the spy when he's not needed. As Jeffrey said, your team just ends up just being a man down if you can't reach the other team and decloak effectively.