The biggest drawback is that you need about a three times as large dp as a spell slinger for the same result.
Without Practiced Alchemist, that's basically true. But with it, a fairly high initiate grade will be enough to bring your final pool up to par.
(6Mag+6Alchemy= 4 average; 6Force= 2 average resist → 4-2 = 2 Potency
↳ 6Force+2Potency+1 Practiced Alchemist+3 initiate grade = final pool of 12)
Add Firebringer mentor spirit and a spec in the appropriate trigger, and you get those 12 dice at initiate grade 2 instead (grade 1 for manipulation spells). Which is good, because there aren't all that many metamagics that a dedicated alchemist would want.
As you probably know, alchemy has two main benefits over sorcery to compensate for the lack of flexibility and raw power: Deal with all of your drain before the run, and Sustain spells for a few minutes without penalty.
These two points together mean that the best use of alchemy is to amass a bunch of buffs (for yourself
and the rest of your team) like Deflection. Also, to avoid resisted rolls wherever possible (cuz lower spell dicepools→ fewer hits→ no effect at all).
There are some specifics that will be GM-dependent, like whether you can decide anything about the spell after the prep is created. For example, could you make a pair of gloves be the lynchpin of a Magic Fingers prep, and set the prep so that the conjured hands mimic the movements of those gloves?
- The books don't say, so that kind of thing will be up to the GM.