Phentermine doesn't suck. I take Adipex 27.5 mgs and 1 or 2 tablets does me nicely.
I mean, your not going to get "high", and yes it has made me bug out on high doses.
If you need energy, or really need to wake up on a Monday morning... phentermine is ideal. It's way more powerful than caffine. It is a diet drug easily perscribed if you ask for it or easily available on the internet. However, most online services charge you an arm and a leg to ship the shit and I honestly wouldn't pay more than $2-3 a pill. As for as I know 27.5 is the highest dose they make, so try to get that... anything less and your wasting your time.
And on a final note... start with one or 2... see how you feel. Don't go taking 6 just because you have heard it's weak.
Side effects are the same as any amphetamine class drug... limp noodle, sweats, chain smoking...ect.