just wondering what the best way to spend gems is

It's up to preference and with any suggestion your mileage may vary, but here's my personal opinion; Most important thing is the infinity forge. It makes you able to skip points put into forge recharge perk to use in better perks, and able to use forges indefinitely so you can do very fast resets easy and don't need to wait for charges, and the bonus exp that comes with it helps a great deal too. Fishing hats are a nice addition if you can afford them, each one gives more and more fishing exp, which means more fishing levels, which means quicker catches and more fish per catch since you get more fish for every fishing level. I'd suggest at least one hat, and if you got spare gems, buy stacks of hats to get fishing exp for days and make quick ascensions pay off. The only down side to this one is that fish become a moot point besides getting AP for ascension, I got way too many fish and no use for them. The overlord miners are nice, more exp and more ore is always great, since ore tends to be the bottleneck. Definitely go for all six miners when possible. AP per ascension multiplier is exceedingly helpful for both quick resets and longer runs. And card slots, while a new concept, have potential to have powerful combos, so if you got an influx of gems, open up all ten slots. Purchases to avoid? Buying candy from gems, extra token drop rate for event, card packs, and high amounts of the rift bonuses. You can earn or get candy from event tokens and as a raid drop, which is more than enough, candy really is not worth the gem price. Tokens drop plentiful if you're active enough, and the well never pays out, I only got one 'golden chicken' card from 5000~ tokens and the card effect is worthless, so getting extra tokens is a waste of gem. The rift bonuses feel very weak to me, I have a 10x multiplier for every rift permanent (from a 250 kred paywall offer, thx MyPoints), but even with such an insanely high multiplier the rifts feel so weak. Gold gain rift is insanely low compared to fighting, the strength bonus rift is decent but not really powerful, the offline and away bonus rifts don't really give a high enough bonus, and the attack speed rift levels too slow and too low of amount: And gaining souls is PAINFULLY slow, and you lose souls on ascensions, so until they buff or balance rifts it's easy to pass on the gem shop bonuses to rifts for now in favor of the other permanents. If you're overflowing with gems and have points in absolutely everything, buying raid tickets can be beneficial; you can find some very nice drops in the raids, like gem candy, high level star cards and the boss cards, but it's a matter of luck. Works much better in combination with raid drop cards equipped.