typical problems with low end int. tube amps?

The two biggest problems I find with low end tube amps are:

1) Lack of power - Jolida
2) Lack of refinement - Rogue

Either one can be addressed via other components in the chain. But for me, personally, I find lack of refinement to be a problem several orders of magnitude worse. You can always find a way to make up for a lack of power - mostly through a more efficient loudspeaker or a nifty device I have discovered which doubles the loudness of a system.

If you happen to pick up an amp which has both, you are REALLY working against yourself.

The other problems you may face, and may or may not be important to you are deficiencies at the frequency extremes. These are mostly a function of circuit topology and transformers, but can be altered to varying degrees by tube selection.

Rouge and lack of refinment are pretty funny. You cant be serious.

I am on a budget as well and always wanted a tube amp. But, do to the usual high prices of a good tube amp, I opted for a good SS amp instead. Because of McIntosh's reputation, I decided to get an old MC 2100 in excellent shape and found one here on Audiogon. Needless to say, it sounded much better than my Yamaha receiver, but still had the typical brightness, sometimes harsh, sound so familiar with SS amps. I've tried different interconnects and even they didn't really do much to tame the high's. I have a pair of Acoustic Research Hi-Res AR9 towers which are definately not the best speakers, but do a decent job. They have a sensitivity rating of 92 db @ 1 watt and can be played at ear bleeding levels. Needless to say, I was looking on this site one day and found a Jolida JD202A intergrated tube amp for sale. For $395.00 and 7 months old, I couldn't pass that up. It's been a little over a month now and I couldn't be happier. That amp was definately the best purchase I have ever made for my system. The Jolida amp "does NOT" lack power as previously stated. My amp is rated at 40 watts per channel and can easily power most speakers with ease. I wouldn't consider hooking up a pair of power hungry Magnepans to it, but most speakers of at least 87/88 db sensitivity will work perfectly fine. You said that your Von Schweikerts are 91 db, so you would have no problems at all. The stock Chinese tubes that came with the amp sounded really good, but I soon replaced with Electro-Harmonix tubes and the sound was smoother and sweeter than before. What I'm getting at is that a tube amp will definately make a huge difference for the better. My speakers sound better than they ever have. I have 10 inch sidefiring woofers in them and the bass is unbelieveable. The overall tonal quality is excellent, as my speakers always leaned more towards the overly bright and sometimes harsh upper frequencies of the spectrum. And now to answer your questions, the only problem that I found is that why it took me this long to finally purchase a tube amp.... :-)Honestly, there are no problems. The soundstage is incredible, no muddiness, not thin, and definatey fine in the bass department.Of course, speaker placement has an awful lot to do with how they're going to sound. Positioned well and the use of good interconnects will bring you to audio bliss. If I was able to do it all over again, I would've done it again! I hope this helps you out some.

How about a hybrid (intergrated or separate)? That's what I use currently. A tube pre will impart just enough of the warmth you're looking for.

Jolida makes a hybrid intergrated that just may be what you're looking for.