i think that part of teh issue with the older style wombolts is the climate in which they were released. it wasnt cultifornia 4 pegs smash your bike off a ledge for 3 hours then go blast a 20 stair on pitta bread tyres. wombolts came out when it mandatory to include a weight as a part of your bike check, and i think the design suffered due to having to be released in a market where if a product was too heavy it just wouldnt sell.
odyssey have always been sweet about their warranties, and subsequently revised the cranks beefing them up considerably. ive not heard of any thunderbolts break (although maybe the market share suffered as a result of the earlier models breaking so theres less out there to break). basically any steel crank is going to break at somepoint, unless you run powerbites instead (and even then they break sometimes if you put them on wrong or your xLaZx), at least odyssey hook you up if theirs do break which is one of the main reasons why i like to support them, even if theyre totally not cool in the bmx nerd scene anymore