I'll be hitting 7th level Mystic soon, Mindbreaker connection changing to a homebrew Conjurer archetype.
But the purpose of this thread is your options on the Haste and Slow spells.
I've always been a fan of haste like effects in RPG spells but people on this forum seem to really talk up Slow.
What are the advantages and disadvantages of each in SF?
Haste is mostly useless. Mystics, Technomancers, Envoys, Mechanics and Operatives don't get much out of it. Only Soldiers and Solarians have access to more full attacks thanks to it. So, if you have a party with a lot of Soldiers and Solarians, Haste is awesome. But in a standard party, you won't even lose an action to cast it.
Slow is the best save or suck in the game. It was good in Pathfinder, but in Starfinder, it's among the rare spells which has been improved, making it a clear no-brainer.
- A slowed character can't make attacks of opportunities and can't move and attack in the same round. So, you just have to avoid enemy melee characters and they won't do anything during 7 rounds.
- Spellcasters can't move and cast spells, so they have to risk an attack of opportunity if they want to cast (there are spells with no attack of opportunity, but they are low level spells mostly).
- An enemy can't switch weapon and attack unless he has Quick Draw. So, if an enemy has a rifle in hand, you can safely go in melee range, and he'll take an AoO or don't do anything.
- Flying creatures can't attack unless they have perfect maneuvrability.
- It takes a full round to stand up from prone or reload a gun.
- Enemies can't full attack (and when you know how easy it is to hit in Starfinder, it's nearly 50% less damage).
Considering that it's a multi target spell, asking for a Will saving throw without being mind-affecting...
Haste is good for characters who want to move a long distance, which can be anyone, depending on the encounter.
Haste is good for people who want to get to somewhere else and then full attack. While that does do more good for some characters than others (an envoy who wants to use a move action improvisation and a standard action to for an attack/ally buff combo is less likely to use it), the claim that only soldiers or solarians have use for it is not correct. Melee mystics and technomancers also benefit from the ability to move up to someone non-adjacent before full attacking, as do certain operative builds that have more use for triple/quad attack, instead of always using trick attack.
Ranged attackers do also sometimes benefit from the ability to move to get a clear shot and then full attack.
It is accurate that haste is a lot less potent than its Pathfinder predecessor, and it is accurate that you need to look at your party to determine how good it is. Slow will be a handy trick for any party, though.
Haste in Starfinder isn't a great spell like it was in Pathfinder. It's useful, but mostly for melee characters that don't otherwise have an ability to move and full attack (ranged characters can largely stand in place and make full attacks).
Slow on the other hand stops an enemy from making full attacks and makes them choose between a single standard action and a move, which is pretty powerful. But also has a chance of failing with the save.
If I could choose only one of the two, I'd probably go with Slow.
The other issue with Haste is that a lot of the benefit it provides (the speed boost) doesn't stack with a common augmentation that a lot of people are going to want to get to have their speed permanently boosted.
Thats true. Most of the secondary benefits of haste can be replicated with (relatively) cheap augments that the spell doesn't stack with.
It's basically an extra move action, which may or may not be useful depending on circumstances.
Haste is a situational spell. In some circumstances, it's the best spell for the job (combat with a lot of movement, or if you need to get to the sniper on the other side of the canyon). But it's not usefull on a regular basis. It's a good candidate for a Spell Gem.