The best part about fortnight is that their support system helps you in every step they do not only to develop but also after launch too! I have used this service for my last two projects where there were many issues with app store approval process from apple due some technical errors (i am sure it was). But still i recommend them as good platform if anyone wants quality services at an affordable cost compared others which are very high end platforms like AWS or Azure etc. No specific issue so far though we had few minor bugs during development time when our product got accepted by Apple Store Review Team everything went smooth now no major problems faced till date.