nirvana used to be, at least, a really good entry level breeder. i had great results with a lot of their stuff a few years back at least in the viability department and to their "credit", their sativa seeds line highland thai (full moon) totally lives up to ALL of the traits associated with real highland thai including being hermie prone and a general fussy bitch to flower, so it's not watered down like many strains claiming to be IBLs that are really just hybrids.
as to sexing plants, it's not that hard really. if you see a claw shaped knob, it's a male and if you see a couple hairs sprouting, it's a female. really, you're better off with regs than fems. feminized seeds can turn hermie and the general consensus seems to be that regular plants are a little healthier with more vigor. i also prefer regs for breeding purposes but not every breeder offers their best in regs.
if you order like RIGHT NOW from attitude, you can get 5 great femmed freebies to play with too plus whatever extra UFO freebies you qualify for with this month's newsletter offer ending tomorrow. those freebies are a great way to try new stuff out. some of my favorite strains started out as freebies like sativa trans love that might have the same euphoric clear headed motivational buzz as a lot of jacks & hazes, but makes the buds and resin like it thinks it's an indica. until i find better, it's going to be a staple in my garden but i've also liked short stuff's super cali haze, DNA's lemon skunk and even short stuff's onyx despite the yucky diesel taste because it had an awesome buzz. i'll NEVER understand the appeal of smoking a truck exhaust.
if you were to buy just 3 regular seeds for any strain, you have a 75% chance of getting at least one female. it IS statistically possible though to buy an entire 5 pack and get all males. that happened to some whizzed off camper a couple years ago, but the odds are only something like 1:12,000 of that happening, nowhere near as impossible as they thought.
back to nirvana, DON'T buy either their fems or their autos. i've seen nothing but grief with those, but their regular seeds are decent enough. if you bought their indoor pack, you'd get up to 5 different females to test. they'd only be average grade knockoffs, but it's a cheap way to learn the ropes.
here's to hoping you find strains that are EXACTLY what you like. TGA is a fairly safe bet though. the worst review i've seen was for one "average & uninspiring" strain by a reviewer that loved everything else and a lot of praise otherwise. like someone told me before i tried the JC2, TGA's gear is legit. if it's claimed to get you high, it really does and if it's claimed to be stony, it'll fuck you up. (basically, his gear does what it promises and he puts a lot of time and effort into making extra special crosses) you just have to try TGA's gear to see for yourself. i used to be skeptical. all that praise sounded too good to be true.